I just traded in my 2007 S550 (bought March 2006) with 24,000 miles on a new 4matic with almost every option (list $107k). Obviously I loved my 2007, or would not have bought the 2008. There is a big difference in both the driving and mileage of this one versus my 07. The new one is both 4matic and has the AMG appearance package. It drives more like a BMW, but gets much less gas mileage than the 2 wheel version. By the way, my old one had no reliability issues during the 2 years of ownership.
Ride, power, back-up camera, looks of AMG ground effects, GPS
I think that they should offer the S350 stateside. Their online link system often does not answer and often the people don't know the answer. Must call dealer service dept for answer. I now cancel the link after the free year runs out.