Best Driver's car is such a weird thing to pin down. It's nearly impossible to come up with one universal answer.
Take the 911 GT3 for example.
Amazing car, obviously.
There are those with years of track experience under their belt who have never been in a RWD Porsche. They might go half way around Road Atlanta in a GT3, for the first time, and literally scare the crap out of themselves on turn 3 and 4. Especially if they don't take special care. A GT3 is not the kind of car that you can easily throw around a corner.
Though, there are others who consider the GT3 to be pure driving nirvana.
Different strokes for different folks.
I imagine the best contenders are going to be the: 911 4S; Stingray; and Cayman. The 4s will more than likely win it.
Porsche seems to have the feedback dialed in a little better than the Stingray, and most people find more comfort in the slightly less powerful car with AWD.
They will say the GTR is a little too big and numb, that the Viper and GT3 are scary at the limit, and that every other car doesn't place for some silly niggle or another.
The only thing you can take away from these articles is performance figures and occasionally tid bits of semi-universal complaints. For example, I am in the market for a Z06. Probably the very first thing I will do (if I go to Road Atlanta this year) is change out the seats.