We studied public online reviews of car-rental services at Denver International Airport to identify factors shaping customer perception. We collected reviews in October 2026. We selected Avis Car Rental, Budget Car Rental, Enterprise Rent-A-Car, Hertz Car Rental, National Car Rental, and SIXT Car Rental because each brand met our eligibility criterion of at least 6,000 reviews found for the airport location. We analyzed whole reviews and their individual claims. A whole-review label captures an overall tone. Claim-level labels capture distinct positive, neutral, or negative points within a review. One review can praise one aspect and criticize another.

We examine how praise and complaints recur or differ across the six brand datasets. The analysis considers staff praise, practical positives, negative topics, and problem resolution. Whole-review and claim-level sentiment offer distinct views of customer perception.

Overall review sentiment across the researched datasets

Among the six analyzed Denver International Airport datasets, National Car Rental had the highest share of positive reviews, at 87.4%. Hertz Car Rental had the lowest, at 33.5%. Negative reviews accounted for 66.0% of the Hertz dataset and 12.6% of the National dataset. These figures describe the analyzed reviews, not all customers’ experiences or a ranking of providers.

Positive reviews made up 79.9% of the Enterprise Rent-A-Car dataset and 77.3% of the Avis dataset. Negative reviews accounted for 16.6% and 21.2%, respectively. For SIXT, 73.8% of reviews were positive and 25.1% were negative.

Budget’s distribution was closer to Hertz’s. Positive reviews made up 34.3% of the Budget dataset, while negative reviews made up 62.1%.

Neutral reviews made up a small share of each dataset: 0.0% for National, 0.5% for Hertz, 1.0% for SIXT, 1.5% for Avis, and 3.5% each for Budget and Enterprise.

Whole-review sentiment compresses mixed experiences into one overall label. Our analysis also examines sentiment in individual claims, staff praise, practical positives, and complaints about problem resolution. These findings describe the reviews analyzed. They do not establish why experiences occurred or how all rentals at Denver International Airport were experienced.

Sentiment within individual customer claims

A review can contain both favorable and unfavorable points. Claim-level percentages describe sentiment assigned to individual claims. Whole-review percentages describe the overall tone of complete reviews.

Positive claims outnumbered negative claims in four datasets. National had the highest positive share, at 66.5%, and the lowest negative share, at 15.1%. Enterprise followed with 57.0% positive and 19.8% negative claims.

Avis and SIXT also had more positive than negative claims. Positive claims represented 56.9% of Avis claims and 55.3% of SIXT claims. Negative claims represented 24.7% and 25.6%, respectively.

Negative claims outnumbered positive claims for Budget and Hertz. They made up 51.2% of Budget claims and 46.7% of Hertz claims. Positive claims accounted for 23.6% and 26.0%, respectively.

Neutral claims made up a smaller share than positive or negative claims in several datasets. Their share was higher for Hertz and Budget, at 27.4% and 25.3%. National and Avis had the lowest neutral shares, both about 18.4%.

These measures use different units. A review can contain several claims, including praise and criticism, so claim shares are not review shares or rates among all rental customers. The results describe the six analyzed datasets rather than ranking providers.

Complaint topics across the researched datasets

Problem resolution recurs among negative reviews in all six datasets. The topic appears in 16.7% of negative Avis reviews and 34.7% of negative SIXT reviews. Its share is 21.1% for Budget, 30.3% for Enterprise Rent-A-Car, 20.8% for Hertz, and 20.0% for National Car Rental. This repetition marks a shared theme in the negative feedback analyzed. It does not show how any particular case was handled.

Other negative topics vary by brand dataset. Speed and efficiency appears in 45.2% of negative Avis reviews, the highest share for this topic among the six datasets. The comparable share for SIXT is 4.1%. Budget’s share is 25.2%, compared with 15.2% for Enterprise Rent-A-Car, 16.2% for Hertz, and 20.0% for National Car Rental.

Product and service quality is the leading topic in National Car Rental’s negative reviews, at 40.0%. The corresponding share for SIXT is 10.2%.

These percentages use negative reviews in each dataset as the denominator. A negative review can describe more than one issue, so the percentages may overlap. The results describe reported topics, not the share of all rentals involving a problem or a ranking of providers.

Top positive patterns by company

Positive staff or customer-service feedback appears among the leading patterns in all six brand datasets, although the labels and ranks vary. Service praise ranks first for Avis, SIXT, and Enterprise. National’s staff evaluations rank first, while favorable service ranks second. Budget’s staff feedback ranks second. Hertz’s leading positives include service, overall rental-experience praise, and easy pickup.

Service praise appears in 11.1% of Avis reviews, 11.6% of Enterprise reviews, and 11.3% of SIXT reviews. Positive staff feedback appears in 7.1% of Budget reviews and 8.0% of National reviews. These are shares of review documents. Pattern rankings use the number of claims assigned to each pattern, so the measures differ. The percentages describe only the analyzed datasets.

Other leading positives refer to specific steps or features of the rental. Easy drop-off ranks first for Budget, easy pickup third for Hertz, and easy return third for National. Vehicle cleanliness ranks second for SIXT. Enterprise preference and friendly staff are tied among its leading patterns. A pattern’s absence from a brand’s top three does not establish that it never appeared there.

Across the datasets, positive feedback includes praise for staff and service, alongside practical details that differ among brands. These patterns describe the analyzed feedback, not an overall satisfaction score or a company ranking.

Top negative patterns by company

Negative-pattern rankings use the number of claims assigned to each pattern. The percentages describe the share of review documents associated with a pattern. These are different measures.

Budget’s leading patterns concern pickup and cost. Waiting in line appears in 10.6% of reviews, delays before receiving the car in 8.6%, and extra charges in 8.1%. These patterns do not establish whether the same reviews described more than one issue.

Hertz’s leading patterns include broad negative assessments. Extremely negative descriptions appear in 9.1% of reviews. Poor overall service and shuttle waits each appear in 8.1%. SIXT’s leading pattern is a negative assessment of the overall experience, at 8.2%. Vehicle condition appears in 3.6% of SIXT reviews, and strongly negative views of the company appear in 6.2%.

For Avis, dissatisfaction with the experience appears in 6.6% of reviews, displeasure with the situation in 6.1%, and a very negative experience in 6.6%. Enterprise’s leading patterns include communication problems and calls for improvement, each in 3.0% of reviews, followed by long lines in 3.5%. National’s leading listed pattern is waiting at vehicle return despite a reservation, appearing in 1.5% of reviews.

A review can contain several claims, and the leading patterns differ among brands. These findings describe the analyzed feedback, not the causes of reported experiences or a ranking of providers.

What the combined findings reveal

Whole-review sentiment and claim-level sentiment give distinct views of the six analyzed datasets. Positive reviews ranged from 87.4% of the National Car Rental dataset to 33.5% of the Hertz dataset. Negative reviews accounted for 12.6% of the National dataset and 66.0% of the Hertz dataset. These are differences within the analyzed reviews, not a ranking or a measure of every customer’s experience.

At the claim level, positive claims outnumbered negative claims for National, Enterprise, Avis, and SIXT. The reverse was true for Budget and Hertz. Positive claims made up 66.5% of National’s claims. Negative claims made up 51.2% of Budget’s claims. A review can contain several positive or negative statements, so claim shares are not another estimate of whole-review sentiment.

Positive patterns repeatedly include staff and customer-service praise. Practical positives vary by brand. Examples include easy drop-off for Budget, easy pickup for Hertz, easy return for National, and clean vehicles for SIXT.

Problem resolution appears among negative topics across all six datasets. Its share ranges from 16.7% of negative Avis reviews to 34.7% of negative SIXT reviews. A negative review can describe more than one issue, so the percentages may overlap.

The findings describe the feedback analyzed. They do not establish causes or represent all Denver International Airport renters. We do not rank companies or their branches. This study helps companies identify reported gaps in product and service quality.

Avis Car Rental: positive and negative experiences

In the Avis Car Rental dataset, positive patterns center on customer service and favorable overall evaluations. Positive customer-service assessments appear in 11.1% of reviews. Highly positive experiences and high service ratings each appear in 10.6%. These patterns describe favorable impressions without identifying one specific service feature as the source of praise.

The leading negative patterns are broad assessments. Dissatisfaction and descriptions of a very negative experience each appear in 6.6% of reviews. Expressions of displeasure appear in 6.1%.

Overall, 77.3% of reviews in the Avis dataset were positive and 21.2% were negative. In the separate claim-level analysis, 56.9% of claims were positive and 24.7% were negative. A review can contain several claims, including favorable and unfavorable points, so these measures need not match.

These percentages describe the analyzed Avis dataset, not all customers or rentals at Denver International Airport. They do not establish why an experience occurred. The findings fit the broader pattern of staff-related praise alongside negative experiences whose specific themes vary across brands.

Budget Car Rental: positive and negative experiences

In the Budget Car Rental dataset, positive feedback includes easy drop-off, positive staff experiences, and friendly, pleasant agents. These themes appear in 9.6%, 7.1%, and 6.6% of reviews, respectively.

In this dataset, 34.3% of reviews were positive, 3.5% neutral, and 62.1% negative. Whole-review sentiment captures an overall tone. The patterns identify specific experiences.

Waiting and delays lead the negative patterns in this dataset. People waiting in line appear in 10.6% of reviews. Delays before receiving the car appear in 8.6%. Extra charges appear in 8.1% of reviews.

Among negative Budget reviews, 21.1% concern problem resolution, 26.8% service quality, and 25.2% speed or efficiency. A negative review can describe more than one issue, so these percentages may overlap.

The dataset includes staff praise and practical positives alongside complaints about waits, charges, and resolving problems. These findings describe the analyzed reviews. They do not establish causes or rank rental providers.

Enterprise Rent-A-Car: positive and negative experiences

Positive sentiment characterized 79.9% of reviews in the Enterprise Rent-A-Car dataset, negative sentiment 16.6%, and neutral sentiment 3.5%. At the claim level, 57.0% of claims were positive, 19.8% negative, and 23.3% neutral. These measures use different units, whole reviews and their component claims, so they need not match.

Positive patterns include service and staff praise, as well as reviewers’ preference for Enterprise. Staff praise and preference each appear in about 12.1% of reviews. Positive descriptions of customer service appear in 11.6%.

The leading negative patterns describe different frustrations. Long lines appear in 3.5% of reviews. Calls for Enterprise to do better and reports of a lack of communication each appear in 3.0%. Waiting during the rental process also appears in 3.0% of reviews. These patterns cover waits, communication, and broader dissatisfaction without establishing why the experiences occurred.

Staff and service praise appears alongside complaints about waits and communication across the Enterprise dataset. Whole-review tone and claim-level sentiment offer complementary views of the feedback.

Hertz Car Rental: positive and negative experiences

In the Hertz Car Rental dataset, good service appears in 8.1% of reviews. Positive descriptions of the rental experience and easy pickup each appear in 7.6% of reviews.

Among all reviews in the Hertz dataset, 9.1% characterize the experience as extremely negative. Poor overall service and waiting or expecting to wait for a shuttle each appear in 8.1%. These patterns combine broad service assessments with a specific transport concern.

Shuttle waiting is the most specific of the leading negative patterns. The other leading patterns summarize reviewers’ overall assessments. Problem resolution appears in 20.8% of negative Hertz reviews. A negative review can describe more than one issue, so the percentages may overlap.

Negative sentiment characterizes 66.0% of Hertz reviews and 46.7% of claims. Positive sentiment characterizes 33.5% of reviews and 26.0% of claims. The first measure assigns an overall tone to a review. The second classifies its component claims. Hertz’s reported positives and complaints show how praise for a process can coexist with dissatisfaction about the experience.

National Car Rental: positive and negative experiences

In the National Car Rental dataset, positive feedback includes employee praise, favorable service descriptions, and easy returns. Employee praise appears in 8.0% of reviews. Favorable service descriptions and easy returns each appear in 11.1%. These are distinct patterns. They do not mean every positive review mentioned staff or the return process.

A leading negative pattern describes waiting at vehicle return despite a reservation. It appears in 1.5% of reviews. Negative-topic findings provide a separate measure. Product or service quality appears in 40.0% of negative reviews, and problem resolution in 20.0%. One negative review can describe more than one issue, so the percentages may overlap.

The leading negative pattern identified in National’s reviews concerns waiting at vehicle return despite a reservation. Among negative-topic findings, quality concerns appear more often than problem-resolution concerns. Problem resolution also recurs in this dataset. The positive patterns highlight employees, favorable service, and easy returns. Negative findings describe return delays and concerns about quality or resolving problems.

These findings describe one brand’s feedback. They do not establish the causes of reported issues or rank rental companies.

SIXT Car Rental: positive and negative experiences

In the SIXT Car Rental dataset, highly positive descriptions of customer service and clean vehicles each appear in 11.3% of reviews. Kindness and friendliness appear in 10.3%. These positive patterns concern both interactions and the rental itself.

A broadly negative description of the experience is the leading negative pattern by claim count. It appears in 8.2% of reviews. Vehicle condition ranks next by claim count and appears in 3.6% of reviews. A strongly negative opinion of the company appears in 6.2%. The rankings use claim counts, while these percentages describe review documents. The second-ranked pattern therefore does not have the smaller document share.

Problem resolution appears in 34.7% of negative SIXT reviews. This topic sits alongside broad dissatisfaction and vehicle concerns. The findings do not establish why a problem occurred or how it was handled.

SIXT’s analyzed feedback includes praise for service, cleanliness, and friendliness, along with broad dissatisfaction and specific concerns about vehicle condition and problem resolution. Whole-review tone and component claims capture different aspects of customer perception. These results describe this dataset rather than ranking providers.

What the findings add up to

Across the six brands, review-level and claim-level sentiment describe different aspects of customer perception. Positive reviews made up 87.4% of the National Car Rental dataset and 33.5% of the Hertz dataset. Negative reviews accounted for 66.0% of the Hertz dataset. At the claim level, positive claims made up 66.5% of National’s claims. Negative claims accounted for 51.2% of Budget’s claims and 46.7% of Hertz’s claims. One review can express several positive or negative points, so claim sentiment need not mirror the tone assigned to a whole review.

Problem resolution recurs among negative topics across all six brands. The share ranges from 16.7% of negative Avis reviews to 34.7% of negative SIXT reviews. One negative review can describe more than one issue, so the percentages may overlap.

Positive patterns repeatedly include staff and customer-service praise. Practical positives vary among brands, including easy drop-off for Budget, easy pickup for Hertz, easy return for National, and clean vehicles for SIXT. Negative-pattern findings also differ, with queues, delays before receiving a car, and extra charges among the reported concerns in Budget’s dataset.

These findings describe the feedback analyzed, not the causes of reported experiences or the views of all Denver International Airport renters. We do not rank companies or their branches. This study helps companies identify reported gaps in product and service quality so they can improve them.

Figures come from the analyzed public-review datasets. Overall review sentiment and sentiment within individual claims use separate denominators.

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