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 4-cylinder, 16-valves 163hp unit, while the other one gets its power and torque from a 4-cylinder, 16-valves 150hp 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. Still, apart from the official crash test results there are other things we need to be aware of. 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. Furthermore, when it comes to weight, a factor that most people underestimate, CLK offers a potentially life-saving difference of 31% 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, at least on all of the models level. These are the official statistics, 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 CLK 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 CLK rank it on average as 4.7, while the one under the competitor's bonnet gets 4.3 out of 5.

BMW is undoubtly more agile, reaching 100km/h in 1.6 seconds less than its competitor. Still, it lacks the power to win the top speed competition, topping at 220 kilometers per hour, 5km/h less than the other car. When it comes to fuel economy the winner has to be BMW Z4, averaging around 7.5 liters of fuel per 100 kilometers (38 mpg), in combined cycle. We can't ignore that 15% difference compared to CLK.

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 being considerably quicker, thus putting more smile on driver's face. To make things even better, it consumps less fuel! All together, there's not much more to say, in this case I wouldn't even consider anything but 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 thousands of similar, yet so different vehicles.