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 sports car segment and utilize the same 2-door cabriolet body style and the rear wheel drive system, it all comes up to the specific petrol engine choice they offer. The first one has a Porsche-engineered powertrain under the hood, a 6-cylinder, 24-valves 400hp unit, while the other one gets its power and torque from a 8-cylinder, 32-valves 571hp 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 sports car segment, which is generally classifying them somewhere in the middle 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, SLS offers a considerable difference of 10% more metal.

I don't like generalizing things when it comes to reliability, although it does seem that Mercedes Benz does have a slight advantage, at least on all of the models level. These are the results of an independent reasearch, while our visitors describe reliability of Porsche with an average rating of 3.9, and models under the Mercedes Benz badge with 4.3 out of 5. Some independent research have also placed 911 as average reliability-wise, and SLS is more or less at the same level.We should definitely mention that owners of cars with the same powertrain as 911 rank it on average as 3.0, while the one under the competitor's bonnet gets 5.0 out of 5.

Mercedes Benz is a bit more agile, reaching 100km/h in 0.9 seconds less than its competitor. In addition to that it accelerates all the way to 317 kilometers per hour, 16km/h more than the other car. When it comes to fuel economy an obvious choice would be 911, averaging around 9.7 liters of fuel per 100 kilometers (29 mpg), in combined cycle. That's 36% difference compared to SLS!

Mercedes Benz is apparently more reliable, not too much, but just enough. 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, SLS offers significantly better overall protection, taking the lead here. It all continues in the same direction, with Mercedes Benz outracing its opponent in any situation possible, making it better choice for boy racers. It does come at a cost though, and that's the fuel consumption... At the end, as much as I'd like to give you a winner here, it's simply a pure tie if you ask me. 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 thousands of similar, yet so different vehicles.