I just got the latest issue of Road & Track. The title of the issue: Outrageous! Nissan's GT-R
Spanks Porsche 911 Turbo and Corvette Z06.
They tested the three cars at Buttonwillow raceway with Steve Millen at the controls. Laptimes for each: Nissan 1:56.9 (84 MPH Avg); Porsche 2:02.1 (80.4 MPH Avg); Corvette 2:02.2 (80.3 MPH Avg). They ranked the Nissan first, Corvette second and the Porsche dead last.
Now, I am sure that with all the technical enhancements in the GT-R, I could turn much faster laps than in the Porsche Turbo. With the ATTESA E-TS (try explaining that to your friends) the Nissan practically drives itself. However, I am not sure that it is a good thing. The excitement and pleasure of driving is that you are the one who is controlling the car. There is a sense of accomplishment when you can push it to its limit (or in my case somewhere generally around the limit) and adjusting your line with throttle inputs, brakes, steering.... so on and so forth. It seems that all you need with the Nissan is to point the car and mash the throttle as much as your courage allows.
I also have a problem with their subjective ratings (always did). They rated the Porsche dead last in driving excitement, brakes, handling, exterior styling and ergonomics/controls. They also rated it second best in engine and steering. I have not driven a Z06 or a 911 Turbo. However, I have driven a current Corvette as well as a 911 Carrera S. I thought the handling, driving excitement, steering, brakes, fit/finish, ergonomics and exterior styling of the 911 S was far superior than the Corvette.
Last and most important point - the GT-R is
UGLY 
It is just massive with awkward lines and angles. The Corvette is just rather plain. (Not to offend any Corvette owners... current styling does not invoke any feelings - good or bad; and makes me long for the Vettes of the 60's)
I guess I am biased but even with the test results... I would choose the 911 Turbo.