As much as the CLS63 is a fast beast, it is completely different than the M3 and not anywhere near as much fun IMO. I have druven one on the track and it was surprisingly capable for a big car but it was big and felt heavy to me and not edgy enough. I would get bored of it as a daily but that is just me.
What about an M5? I don't know why that seems like a better compromise to me but it does. Having said that, I found the M3 to be a great and comfortable daily car and I would take it over the others you mention if for no other reason than it is a bit edgier and fun and doesn't feel like a big boat. All subjective.
2014 Corvette Stingray | Torch Red | Z51 | On order...
2012 C63 coupe | Obsidian Black | Performance Package (481hp, 443ft/lbs) | Sold
2011 M3 coupe | Jerez Black | ZCP/DCT | Sold but never forgotten nor will the love affair end
2010 M3 coupe | Alpine White | 6MT | Sold