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 BMW-engineered powertrain under the hood, a 6-cylinder, 24-valves 340hp unit, while the other one gets its power and torque from a 6-cylinder, 24-valves 306hp 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? Furthermore, when it comes to weight, a factor that most people underestimate, BMW Z4 offers a marginal difference of 4% 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. 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. 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 BMW Z4 rank it on average as 3.0, while the one under the competitor's bonnet gets 5.0 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 the winner has to be SLK, averaging around 7.1 liters of fuel per 100 kilometers (40 mpg), in combined cycle. We can't ignore that 27% difference compared to BMW Z4.

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, BMW Z4 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. It does come at a cost though, and that's the fuel consumption... I believe that, when we take all into account, we have only one winner here - the Mercedes Benz. Anyway, that's the most objective conclusion I could've came up with and it's based solely on the information found on this website. Aspects such as design, practicality, brand value and driving experience are there for you to measure them out. 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™, among thousands of similar, yet so different vehicles.