they're all dope as fuck.
each company offers beasts, to argue over which is better is an argument that won't end soon.
I'm personally a bmw guy... the e39 m5 is by far my favorite
as for mercedes, i don't really fuck with them since I like driving a manual gearbox... but i drove the c63 the other day, and god damn......
as for audi, the rs6 is dope as fuck
as for the boss cars... they all offer them: the 760Li, s63/5, cls63, s600, s8, etc.
I've worked valet for about a year and a half now... and i've pretty much driven them all.... i have not however driven the new cts-v.. but i dislike american cars, even when the design of it is based on an archer drawing his bow or whatever the fuck