Tell us what you know about their safety engineering vs. other manufacturers and I'll give your opinion some weight. I'm not sure if you're telling us that you've attempted to repair them without the proper training and equipment or what. It sounds like it did not go well.
I have friends who work on them for a living and they have plenty of gripes but they are coming from an informed perspective. All modern European luxury cars are extremely complicated with computer controlled everything. I'm not the least convinced that Mercedes cars are more troublesome than Jags or Audis or BMWs or whatever and the performance and safety engineering is state of the art. That is what buyers value, not how much the mechanics who change parts on them like them.
