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 5-door wagon 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 272hp unit, while the other one gets its power and torque from a 6-cylinder, 24-valves 258hp engine designed by Mercedes Benz.

The fact that the Audi got tested by the European New Car Assessment Programme (Euro NCAP), while the other contender didn't, puts it sky-high safety-wise, in my eyes at least. 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, still it doesn't help us solve our dilemma, does it? On the other hand, when it comes to weight, a factor that most people underestimate, CLS offers a marginal difference of 5% 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, at least on all of the models level. These are the official statistics, 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. Unfortunatelly, I don't have enough insight that would allow me to comment in more details on the specific models level. That apart, owners of different cars powered by the same engine as Audi A6 rank it on average as 5.0, while the one under the competitor's bonnet gets 2.5 out of 5.

Audi is a bit more agile, reaching 100km/h in 0.8 seconds less than its competitor. In addition to that it accelerates all the way to 250 kilometers per hour, 3km/h more than the other car. When it comes to fuel economy the winner has to be Audi A6, averaging around 5.3 liters of fuel per 100 kilometers (53 mpg), in combined cycle. We can't ignore that 17% difference compared to CLS.

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 beats the other contender by far, making it the best choice without even considering other things. It all continues in the same direction, with Audi 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 Audi. 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. 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.