Two significantly similar cars, no doubt about that. Still, each one has something different to offer. Having both cars powered by petrol 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 (4 x 4 for the Audi and rear in the case of the Mercedes Benz). The first one has a Volkswagen-engineered powertrain under the hood, a 8-cylinder, 40-valves 260hp unit, while the other one gets its power and torque from a 6-cylinder, 18-valves 224hp engine designed by Mercedes Benz.

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, Mercedes Benz S offers a marginal difference of 3% 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, when all the models are taken into account. That's the official data, while our visitors describe reliability of Audi with an average rating of 4.2, and models under the Mercedes Benz badge with 4.4 out of 5. Independent research findings rank A8 as average reliability-wise, and S is more or less at the same level.We should definitely mention that owners of cars with the same powertrain as Audi A8 rank it on average as 3.0, while the one under the competitor's bonnet gets 5.0 out of 5.

Mercedes Benz is a bit more agile, reaching 100km/h in 0.4 seconds less than its competitor. Still, it lacks the power to win the top speed competition, topping at 240 kilometers per hour, 10km/h less than the other car. When it comes to fuel economy the winner has to be Mercedes Benz S, averaging around 11.5 liters of fuel per 100 kilometers (25 mpg), in combined cycle. We can't ignore that 7% difference compared to Audi A8.

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, Mercedes Benz S offers slightly better overall protection and takes the lead. It all continues in the same direction, with Mercedes Benz offering somewhat better performance, just enough to call it quicker. To make things even better, it consumps less fuel! All together, there's not much more to say, in this case I wouldn't even consider anything but 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™, among thousands of similar, yet so different vehicles.