Of those four brands, all current industry surveys show that they are not very reliable at all, with the exception of Mercedes who woke up and made big improvements just a few years ago although some models are still pretty dire. But unless you're getting a new or near-new Merc then you won't benefit from that.
If you want reliability, European styling, and sporty looks and handling then the popular choice is for a Japanese Mazda MX-5 (Eunos in Japan, Miata in America). But at just 17 years old, you'll probably find it far too expensive to insure any open top sports car, and probably anything made by Mercedes. BMW or Audi. The Mazda 3 is an alternative, it has European styling, legendary Mazda reliability, and it's very good to drive. I personally couldn't stand the one my wife owned though as I thought there was far too much ugly black plastic inside, and I also thought that the amount of space inside the car was very poor compared to some other rivals like the Honda Jazz/Fit.