My wife originally went to get a S550, but after seeing the CLS550, she ordered one of those instead. The choice for her came down to looks and style. The CLS just looked like a far more fun and less "stuffy" car that still allowed her to carry at least 3 passengers with their own doors. The leg room in the rear seat is not that bad (if you're under 5'11" and the front driver or passenger doesn't play in the NBA). The S is no doubt roomier, with a slightly more refined interior, and has more "bells and whistles", but the performance, ride, and handling of both cars was outstanding with no real runaway winner (CLS had better handing in mountain curves, the S had a slightly smoother ride, both have great "get-up and go"). As for residual value, from what I've seen, both cars are pretty bad at holding any value, and even worse if you put a lot of miles on them, so any contrast there is just splitting hairs. She still plans on getting a S-class, she just decided to wait until we have kids and need the extra room. Until then, the CLS is a great car that turns heads, is a blast to drive, and starts conversations.