Two significantly similar cars, no doubt about that. Still, each one has something different to offer. Having both cars powered by petrol engines and utilizing the 2-door cabriolet body style within the same 'Sports car' segment, the only major difference here really is their wheel drive configuration (4 x 4 for the BMW and rear in the case of the Mercedes Benz). The first one has a BMW-engineered powertrain under the hood, a 8-cylinder, 32-valves 407hp unit, while the other one gets its power and torque from a 8-cylinder, 32-valves 435hp 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. Still, apart from the official crash test results there are other things we need to be aware of. Both vehicles belong to the sports car segment, which is generally classifying them somewhere in the middle safety-wise, but that fact doesn't break the tie between the two cars. Furthermore, when it comes to weight, a factor that most people underestimate, 6 Series offers a considerable difference of 16% more metal.

Reliability is not the best thing to consider on the make level, but it is worth mentioning 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 BMW 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 6 Series rank it on average as 3.0 out of 5, exactly the same as the other one.

Mercedes Benz 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 250 kilometers per hour, exactly the same as the other car does. When it comes to fuel economy an obvious choice would be Mercedes Benz SL, averaging around 9.1 liters of fuel per 100 kilometers (31 mpg), in combined cycle. That's 25% difference compared to 6 Series!

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 offers significantly better overall protection, taking the lead here. From there things take a different direction, with Mercedes Benz 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 Mercedes Benz. 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. 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 more than 12.000 different ones in our database.