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. Moving further on, let's take a closer look at some additional safety-related facts. 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. On the other hand, taking kerb weight as an important factor into account, SLS offers a considerable difference of 10% more metal.

Manufacturers have been building their reliability reputation for decades now and, generally speaking, it appears that Mercedes Benz does have a slight advantage, all the models observed together. These are the official statistics, while our visitors describe reliability of Porsche with an average rating of 3.7, and models under the Mercedes Benz badge with 4.4 out of 5. Independent research findings rank 911 as average reliability-wise, and SLS is more or less at the same level.Above it all, drivers of cars with the same engine 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 offering somewhat better performance, just enough to call it quicker. It does come at a cost though, and that's the fuel consumption... No mistake, whatever you decide here, but I'd still go for the Porsche. 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. 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™, out of 12.000+ vehicles we currently have in our database.