I'm not buying either one, I was just curious.  My friend's co-worker, whom played poker w/ us the other night, just got one.  He couldn't stop talking about it.  I entertained him and complimented his car and everything, pretended to drool, etc.
But like I said, I was not impressed w/ the comfort level of the automobile.  I love the exterior though, and the interior was leather-clad, but again, not comfortable.
He said he looked at a lot of cars, like the 330Ci, 350Z, etc.  Ultimately, he said he like the options in the G35C over the 330Ci, and particularly the leather dash.
I didn't know that the G35 is 10k cheaper, which is probably his real reason.