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 luxury 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 Mercedes Benz-engineered powertrain under the hood, a 6-cylinder, 24-valves 224hp unit, while the other one gets its power and torque from a 6-cylinder, 24-valves 225hp engine designed by Audi.

The first thing to look into here would be the results from European New Car Assessment Programme (Euro NCAP) tests performed on the two cars. Good thing is that both vehicles got tested, with the same number of safety stars gained in the process. That aside, let's consider some other aspects which affect safety. Both vehicles belong to the luxury car segment, which is generally a very good thing 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 A6 offers a marginal difference of 1% 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. That's the official data, 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. Some independent research have also placed E as average reliability-wise, and A6 is more or less at the same level.That apart, owners of different cars powered by the same engine as Mercedes Benz E rank it on average as 4.5, while the one under the competitor's bonnet gets 5.0 out of 5.

Audi is a bit more agile, reaching 100km/h in 0.3 seconds less than its competitor. In addition to that it accelerates all the way to 245 kilometers per hour, 1km/h more than the other car. When it comes to fuel economy things look pretty much the same for both cars, averaging around 7.9 liters of fuel per 100 kilometers (36 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, Audi A6 offers slightly better overall protection and takes the lead. It all continues in the same direction, with Audi offering somewhat better performance, just enough to call it quicker. Fuel consumption is more or less the same. 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. 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.