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 diesel engine choice they offer. The first one has a Audi-engineered powertrain under the hood, a 6-cylinder, 24-valves 233hp unit, while the other one gets its power and torque from a 6-cylinder, 24-valves 231hp 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. That aside, let's consider some other aspects which affect safety. Both vehicles belong to the executive car segment, which is generally a fortune safety-wise, but it doesn't do much to help us decide between the two. On the other hand, taking kerb weight as an important factor into account, Mercedes Benz S offers a marginal difference of 5% 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, when all the models are taken into account. These are the results of an independent reasearch, 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.That apart, owners of different cars powered by the same engine as Audi A8 rank it on average as 4.6, while the one under the competitor's bonnet gets 4.2 out of 5.

Both of the cars accelerate exactly the same, so we couldn't put one above the other. Car No. 2 is faster though, reaching top speed of 245 kilometers per hour, 2km/h more than the other car. When it comes to fuel economy things look pretty much the same for both cars, averaging around 8.6 liters of fuel per 100 kilometers (33 mpg), in combined cycle.

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, Mercedes Benz S offers slightly better overall protection and takes the lead. When it comes to performance, both vehicles provide similar experience, so I wouldn't point any of them out. Audi A8 still consumps less fuel, which needs to be taken into consideration. No mistake, whatever you decide here, but I'd still go for the Audi. Nevertheless, let's not forget that people have different preferences and needs, so what really counts is your personal feel. I'm only here to help. 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.