Rudy, you are definitely right, I was being too harsh on BMW in my original post. Mercedes has its fair share of problems, and I would be lying if I said Mercedes was any better than BMW in the reliability department. Just for better background, let me explain the situation. I am only 19 so I am still living at home with my parents and two brothers. Being a huge car enthusiast, I do most of the maintenance for the cars and when it's time for a new car, I do all the lease negotiations and stuff...usually, my father doesn't even come into the dealership. Anyways, a few months ago we gave back a 2001 E430 4Matic and a 2001 S500 for two 2004 S500 4Matic's. The E430 and the S500 gave us quite a few problems, and these new S500's are no exception. From the day my father took delivery of his S500, the tire pressure monitor was not functioning at all. And one night when I was driving my mom's S500, the COMAND Center wasn't playing any music! I could change radio stations but no sound would come out! Then the COMAND Center would shut off, then turn back on...how weird is that! But the next morning, the COMAND Center was working fine and the problem just never came back.
So from our experience, Mercedes does have its problems, but most of the time it is things that do not affect the operation of the car itself (meaning, the ability to get from Point A to Point B).
The only trouble-free Mercedes (in our experience), has been our 2002 ML500. We had a 1999 ML430 before that and it was very trouble-free and we were happy with it, so when the ML430 lease ended, we opted for the 2002 ML500. So far, after 22K miles, the ML500 has been running perfect, as well and I think it is due to the fact that the ML500 has signficantly less technology packed inside than an S-Class.
I guess what I'm trying to say is that when you buy a German car (whether it's Audi, BMW, Mercedes, etc.) you are always taking a risk. But in the end, these cars are truly worth it. My dad has been a loyal Mercedes customer since the 1980's (and he grew up with his parents having Mercedes in their garage) and I don't think he will ever trust another car company.