I think I've mentioned before in this thread, I've got a '90 300SE with nearly 294,000 miles on it. The other day I was thinking about letting it go in favor of a newer BMW 750iL with <100k on it, but I just couldn't bear to get rid of the old Nazi battlecruiser.
Nawww, never go from Mercedes to BMW. You will be disappointed.
Mercedes is the shiznit! I had an old '83 300SD that got up to 306,000 before we sold it. Might still be on the road today, who knows? But they last forever, and I love that about them. Plus, they're tanks.