The short answer
The Audi Q8 offers fuel economy, while the Mercedes-Benz GLS excels at power instead. Choose the Audi Q8 if you prioritize fuel economy in daily driving, or the Mercedes-Benz GLS if power matters more for your needs. Both are covered by real owner reports on CarWizz.
Overall
Mixed sentiment with a clear generational divide. The gasoline-powered Q8 (2019-2024) receives praise for its striking coupe-SUV styling, high-quality and comfortable interior, spacious cabin, and refined driving dynamics. However, it is heavily criticized for significant reliability concerns, particularly with major powertrain components leading to costly out-of-warranty repairs, and for very poor resale value.
Best version to buy
For the gasoline Q8/SQ8, the Prestige trim is frequently mentioned as the target for maximizing luxury features. For the performance-oriented SQ8, the Sport Package (including active roll stabilization and a sport rear differential) is specifically highlighted as a desirable option for enhanced driving dynamics.
Known issues
Overall
Sentiment is sharply divided and heavily dependent on ownership phase and powertrain. The vehicle is universally praised for its core attributes: exceptional ride comfort, often described as "like a magic carpet," spacious and comfortable third-row seating, a luxurious and well-appointed interior, and strong, smooth V8 performance in 550/580/63 models. However, this high praise is almost universally tempered by severe criticism of ownership costs and reliability concerns beyond the initial warranty period.
Best version to buy
Insufficient owner data available to declare a single "best" version. Feedback is split by priorities: the GLS 450 is noted for being the entry point with a sacrifice in power.
Known issues
The verdict
The Audi Q8 is the better choice for most buyers.
It has better fuel economy on its best-equipped version than the Mercedes-Benz GLS, based on the data above. If power matters more to you than running costs, the Mercedes-Benz GLS is worth a closer look instead.
Other comparisons
Not sure which one fits you?
Answer a few questions and get a personalized recommendation.
Which is more reliable, the Audi Q8 or the Mercedes-Benz GLS?
Owner reports show similar reliability sentiment for the Audi Q8 and the Mercedes-Benz GLS. Check the known issues listed above for specific differences between the two.
Which is better for families, the Audi Q8 or the Mercedes-Benz GLS?
The Mercedes-Benz GLS seats more passengers than the Audi Q8 on its catalogued best-equipped version. Body type also differs: the Audi Q8 is classed as a SUV, the Mercedes-Benz GLS as a SUV.
Which has better fuel economy, the Audi Q8 or the Mercedes-Benz GLS?
The Audi Q8 is more fuel-efficient on paper: 1.2-1.6 L/100km combined versus 13.3-13.5 L/100km for the Mercedes-Benz GLS, based on the best-equipped catalogued version of each.
Which is cheaper to maintain, the Audi Q8 or the Mercedes-Benz GLS?
Exact maintenance costs aren't in our data, but owner reports mention cost-related concerns more often for the Audi Q8 than the Mercedes-Benz GLS. See the known issues comparison above.