Well, these are two pretty similar cars we have here! It's only details that could potentially make the difference. Considering they both belong to the executive car segment and utilize the same 4-door sedan body style and the 4 x 4 wheel drive system, it all comes up to the specific petrol engine choice they offer. The first one has a Mercedes Benz-engineered powertrain under the hood, a 6-cylinder, 24-valves 367hp unit, while the other one gets its power and torque from a 6-cylinder, 24-valves 340hp engine designed by Volkswagen.

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. Still, apart from the official crash test results there are other things we need to be aware of. Both vehicles belong to the executive car segment, which is generally a fortune safety-wise, but that fact doesn't break the tie between the two cars. On the other hand, when it comes to weight, a factor that most people underestimate, Audi A8 offers a marginal difference of 6% more metal.

Manufacturers have been building their reliability reputation for decades now and, generally speaking, it appears that both brands display similar results in faults and breakdowns, all the models observed together. That's the official data, while our visitors describe reliability of Mercedes Benz with an average rating of 4.3, 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. Above it all, drivers of cars with the same engine as Mercedes Benz S rank it on average as 1.0, while the one under the competitor's bonnet gets 3.0 out of 5.

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 the winner has to be Mercedes Benz S, averaging around 9.4 liters of fuel per 100 kilometers (30 mpg), in combined cycle. We can't ignore that 9% difference compared to Audi A8.

Audi 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! I believe that, when we take all into account, we have only one winner here - the Mercedes Benz. In any case that's my personal view, built upon all the data available to me. What should decide here though is the way you feel about the two vehicles, and I hope you'll find my guidelines useful in the process. In case you have two minutes to spare I invite you to define your needs, desires and budget and see which car would be chosen by the virtual adviser™, out of 12.000+ vehicles we currently have in our database.