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 'Executive car' segment, the only major difference here really is their wheel drive configuration (rear for the Mercedes Benz and 4 x 4 in the case of the BMW). The first one has a Mercedes Benz-engineered powertrain under the hood, a 12-cylinder, 48-valves 630hp unit, while the other one gets its power and torque from a 8-cylinder, 32-valves 625hp engine designed by BMW.

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. Moving further on, let's take a closer look at some additional safety-related facts. Both vehicles belong to the executive car segment, which is generally a fortune safety-wise, still it doesn't help us solve our dilemma, does it? Furthermore, when it comes to weight, a factor that most people underestimate, Mercedes Benz S 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, all the models observed together. That's the official data, while our visitors describe reliability of Mercedes Benz with an average rating of 4.3, and models under the BMW badge with 4.1 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 Mercedes Benz S rank it on average as 5.0, while the one under the competitor's bonnet gets 3.0 out of 5.

BMW 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 305 kilometers per hour, 5km/h more than the other car. When it comes to fuel economy the winner has to be 8 Series, averaging around 10.6 liters of fuel per 100 kilometers (27 mpg), in combined cycle. We can't ignore that 13% difference compared to Mercedes Benz S.

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, Mercedes Benz S offers slightly better overall protection and takes the lead. From there things take a different direction, with BMW being considerably quicker, thus putting more smile on driver's face. 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. 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. 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™, among more than 12.000 different ones in our database.