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 4-door sedan body style within the same 'Luxury car' segment, the only major difference here really is their wheel drive configuration (front for the BMW and rear in the case of the Mercedes Benz). The first one has a BMW-engineered powertrain under the hood, a 6-cylinder, 24-valves 313hp unit, while the other one gets its power and torque from a 6-cylinder, 24-valves 265hp 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 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. Furthermore, taking kerb weight as an important factor into account, 6 Series Gran Coupe 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 BMW with an average rating of 4.2, and models under the Mercedes Benz badge with 4.4 out of 5. Some independent research have also placed 6 Series Gran Coupe as average reliability-wise, and CLS is more or less at the same level.That apart, owners of different cars powered by the same engine as 6 Series Gran Coupe rank it on average as 4.6, while the one under the competitor's bonnet gets 4.8 out of 5.

BMW is a bit more agile, reaching 100km/h in 0.8 seconds less than its competitor. Still, it lacks the power to win the top speed competition, topping at 250 kilometers per hour, exactly the same as the other car does. When it comes to fuel economy things look pretty much the same for both cars, averaging around 5.8 liters of fuel per 100 kilometers (49 mpg), in combined cycle.

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, 6 Series Gran Coupe offers slightly better overall protection and takes the lead. It all continues in the same direction, with BMW offering somewhat better performance, just enough to call it quicker. To make things even better, it consumps less fuel! It's not difficult to say then that if I'd need to make a choice, it would definitely be the BMW. 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. 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™, out of 12.000+ vehicles we currently have in our database.