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 Mercedes Benz-engineered powertrain under the hood, a 6-cylinder, 24-valves 272hp unit, while the other one gets its power and torque from a 6-cylinder, 24-valves 343hp engine designed by BMW.

The fact that the BMW got tested by the European New Car Assessment Programme (Euro NCAP), while the other contender didn't, offers a slight advantage, as the 4-star rating is better than none. 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 it doesn't do much to help us decide between the two. On the other hand, taking kerb weight as an important factor into account, BMW Z4 offers a marginal difference of 3% 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, when all the models are taken into account. These are the results of an independent reasearch, while our visitors describe reliability of Mercedes Benz with an average rating of 4.4, and models under the BMW badge with 4.2 out of 5. The same official information place SLK as average reliability-wise, and Z4 is more or less at the same level.Above it all, drivers of cars with the same engine as SLK 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 0.6 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 the winner has to be SLK, averaging around 10.6 liters of fuel per 100 kilometers (27 mpg), in combined cycle. We can't ignore that 14% 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 beats the other contender by far, making it the best choice without even considering other things. 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... It's really tough to make a final decision here, but if I'd need to, I'd say BMW. 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. 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 more than 12.000 different ones in our database.