I have been driving my CL55 for about 5 years now. I have always loved it. But it has 120K miles on it and so it needed something newer for my ego. I seriously considered another CL63 but got the wife a CLS550 and after driving it I was struck by the similarities. The size of the CLS is akin to the older S class (CL too) and the roof line is even similar. You do notice the CLS is about 500 lbs lighter, so the ride isn't as smooth, also because it doesn't have the ABC hydraulic suspension system, and the CLS has 19" wheels with lower profile tires. Also the CL is quieter by a quite a bit. But just for driving feel/size/fit it is amazingly the same, and kind of has the same appeal. I drove a 2014 S550 and though it is tomb-like in sound isolation, it is also a boat, sure, sneaky fast, but still massive. The 55 growls a little more, and the supercharged engine is meaner than the turbos from a vibration standpoint. But the CLS is a rocket too, just more refined. So...
I think my service contracts paid my dealer about $30K in warranty repairs over those 5 years, so the CL is in great shape, but now I'm going bare! Still, it's my daily driver now, and I still love the off peak hours commute.