Two significantly similar cars, no doubt about that. Still, each one has something different to offer. Having both cars powered by diesel engines and utilizing the 4-door sedan body style within the same 'Executive car' segment, the only major difference here really is their wheel drive configuration (rear for the Mercedes Benz and 4 x 4 in the case of the Audi). The first one has a Mercedes Benz-engineered powertrain under the hood, a 6-cylinder, 24-valves 340hp unit, while the other one gets its power and torque from a 6-cylinder, 24-valves 286hp engine designed by Audi.

Unfortunatelly, neither of the two vehicles was submitted to the European New Car Assessment Programme (Euro NCAP) testing. This makes it virtually impossible for me to pick one over the other and I'm generally against buying such cars as the safety should really always come first. Moving further on, let's take a closer look at some additional safety-related facts. Both vehicles belong to the executive car segment, which is generally a fortune safety-wise, still it doesn't help us solve our dilemma, does it? On the other hand, taking kerb weight as an important factor into account, Audi A8 offers a marginal difference of 2% more metal.

I don't like generalizing things when it comes to reliability, although it does seem that both brands display similar results in faults and breakdowns, all the models observed together. These are the results of an independent reasearch, while our visitors describe reliability of Mercedes Benz with an average rating of 4.4, and models under the Audi badge with 4.2 out of 5. Unfortunatelly, I don't have enough insight that would allow me to comment in more details on the specific models level. We should definitely mention that owners of cars with the same powertrain as Mercedes Benz S rank it on average as 3.0 out of 5, exactly the same as the other one.

Mercedes Benz is a bit more agile, reaching 100km/h in 0.5 seconds less than its competitor. Still, it lacks the power to win the top speed competition, topping at 250 kilometers per hour, exactly the same as the other car does. When it comes to fuel economy things look pretty much the same for both cars, averaging around 5.4 liters of fuel per 100 kilometers (52 mpg), in combined cycle.

Mercedes Benz appears just a bit more reliable, although the difference is truly marginal. The most important thing when deciding between any two vehicles should always be safety, both passive and active. In my opinion, everything taken into account, Audi A8 offers slightly better overall protection and takes the lead. From there things take a different direction, with Mercedes Benz offering somewhat better performance, just enough to call it quicker. To make things even better, it consumps less fuel! No mistake, whatever you decide here, but I'd still go for the Mercedes Benz. Anyway, that's the most objective conclusion I could've came up with and it's based solely on the information found on this website. Aspects such as design, practicality, brand value and driving experience are there for you to measure them out. Also, you could use the oportunity to find out which car, everything taken into account, would be the perfect choice for you in the eyes of the virtual adviser™, among thousands of similar, yet so different vehicles.