Two significantly similar cars, no doubt about that. Still, each one has something different to offer. Having both cars powered by diesel engines and utilizing the 5-door wagon body style within the same 'Luxury car' segment, the only major difference here really is their wheel drive configuration (rear for the BMW and 4 x 4 in the case of the Audi). The first one has a BMW-engineered powertrain under the hood, a 6-cylinder, 24-valves 197hp unit, while the other one gets its power and torque from a 6-cylinder, 24-valves 240hp engine designed by Audi.

Both vehicles got tested by European New Car Assessment Programme (Euro NCAP), with the Audi being a slightly better choice apparently. Still, apart from the official crash test results there are other things we need to be aware of. Both vehicles belong to the luxury car segment, which is generally a very good thing safety-wise, but it doesn't do much to help us decide between the two. On the other hand, if we'd like to consider vehicle mass in this context too, which we definitely should, Audi A6 offers a considerable difference of 11% 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 BMW, as well as Audi, with the same average rating of 4.2 out of 5. Independent research findings rank 5 Series as average reliability-wise, and A6 is more or less at the same level.Above it all, drivers of cars with the same engine as 5 Series rank it on average as 4.5, while the one under the competitor's bonnet gets 5.0 out of 5.

Audi is undoubtly more agile, reaching 100km/h in 1 seconds less than its competitor. In addition to that it accelerates all the way to 245 kilometers per hour, 13km/h more than the other car. When it comes to fuel economy things look pretty much the same for both cars, averaging around 6.6 liters of fuel per 100 kilometers (43 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 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 being considerably quicker, thus putting more smile on driver's face. It does come at a cost though, and that's the fuel consumption... It's not difficult to say then that if I'd need to make a choice, it would definitely be the Audi. 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. I suggest you spend two more minutes in order to find out which car, based on your needs and budget, would be picked by the virtual adviser™, among thousands of similar, yet so different vehicles.