The short answer
Based on available data, the Mercedes-Benz E-class comes out ahead of the Infiniti Q70 on fuel economy and power. Check the specs table and owner sentiment below for the full comparison before deciding between the two. Both are covered by real owner reports on CarWizz.
Overall
Mixed to positive sentiment, heavily dependent on engine choice and model year. The naturally aspirated 3.7L V6 (VQ37VHR) and 5.6L V8 (VK56VD) engines are widely praised for their strong power, reliability, and longevity, with the 3.7L noted as being "rock solid" and the V8 described as "fun as shit to drive." The vehicle is appreciated for its handsome looks, comfortable and capable handling on both back roads and interstates, and spacious interior, particularly in the long-wheelbase (L) models. Significant and consistent criticism is directed at the outdated, overly complicated, and slow infotainment system and gauge cluster, which is described as feeling a generation behind competitors.
Best version to buy
2014 and newer Q70 with the 5.6L V8. This recommendation is based on mechanical quality-of-life updates that addressed known issues from the preceding M56 generation, such as the timing chain and rear-wheel steering.
Known issues
Overall
\nSentiment is mixed and heavily dependent on the specific generation and ownership context. For the W212 generation (approximately 2009-2016), owner feedback is generally positive regarding its solid build quality, reliability, and driving experience, with it being described as "pretty reliable" and "one of the best running cars" Mercedes has produced in recent decades. The W213 generation (approximately 2017-2023) receives praise for supreme comfort, refinement, and technology, particularly in plug-in hybrid (PHEV) diesel variants noted for excellent fuel economy.
Best version to buy
\nFor the W212 generation (2009-2016), the 2014-2017 model years are specifically recommended as being "well sorted." The E350 and E400 models with standard suspension (avoiding AIRMATIC air suspension if reliability is a priority) are cited as rock solid. For the W213 generation, the E300de (diesel plug-in hybrid) estate is highly praised for its combination of comfort, refinement, and fuel efficiency.
Known issues
The verdict
The Mercedes-Benz E-class is the better choice for most buyers.
It has stronger reliability sentiment in owner reports than the Infiniti Q70, based on the data above. If the specific known issues on the Mercedes-Benz E-class are a dealbreaker, the Infiniti Q70 is worth a closer look instead.
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Which is more reliable, the Infiniti Q70 or the Mercedes-Benz E-class?
Owner reports lean more positive on reliability for the Mercedes-Benz E-class than the Infiniti Q70. See the known issues comparison above for the specific concerns owners report on each.
Which is better for families, the Infiniti Q70 or the Mercedes-Benz E-class?
Data on family-specific factors like cargo space is limited for one or both models, but based on available reports, both are positioned as practical daily drivers. Check the specs table above for seating and body type.
Which has better fuel economy, the Infiniti Q70 or the Mercedes-Benz E-class?
The Mercedes-Benz E-class is more fuel-efficient on paper: 0.8-1 L/100km combined versus 13.1 L/100km for the Infiniti Q70, based on the best-equipped catalogued version of each.
Which is cheaper to maintain, the Infiniti Q70 or the Mercedes-Benz E-class?
Exact maintenance costs aren't in our data, but reliability signals above are the closest proxy: fewer reported issues generally means lower repair costs over time.