i got rid of my MB's when it was apparent that i soon would not be able to do much work on them anymore. Even when i had them, big jobs always went to an indy mechanic that specializes in Porsches and Mercedes that was near my home. He's also done the front brakes on my TDI. All the other work my VW has needed has been done by three different VW dealers; two here in Houston and one in Killeen, TX. The Killeen dealer was, by far, my favorite.
I only had one problem ever with the shop that worked on my Benz and it was resolved amicably. I don't think shops are greedy (except some dealers) and I don't think they charge too much. I'm pretty happy with most mechanics and shops. In fact, I'll go one step further and say i'm very grateful to the mechanics and shops that i've used over the years.