I've spent a bit of time in one....being a Vette fan, I was already sold on the merits of the supercharged LS motor and Magnetic Ride (similar to the setup on my C5 Vette, the new ZR1, Ferrari 599, and your old R8), and the value for the dollar is unbeatable. It's just a blast to drive a fast four door, esp with Recaro seats and a stick.
However, if you are a detail freak, the fit and finish, while quite nice overall, is not up to M5/E63 levels.....but then again, neither is the price.
I found my knee ended up hitting the center console a fair bit as well...so that might be a huge issue for you.
Also, the V series coupe will be out later this year....something to consider if you like the polarizing looks.
I'm curious to hear your impressions after driving one! Try to find one with the Recaros if at all possible....