Full disclosure: I have neither driven nor ridden in a GT-R. That said, at every track day I've attended, I'm told by instructors and even some GT-R owners that while the car is stupid fast and fun for that reason, it also kind of just drives itself. Its electronics and AWD let you get away with huge driving mistakes, so if you're interested in refining your driving technique and actually learning, it's absolutely not the right car for you. I also think it's rather ridiculous that running with DSC completely off is grounds for voiding your warranty; it's almost as if the engineers view the driver as some sort of inconvenience or blemish on their example of automotive perfection. But if you want to go stupid fast and you're willing to sacrifice some luxury, comfort, (IMHO) aesthetic appeal, and extra cash, then by all means.
Just remember that the GT-R isn't quite as big a bargain as it appears, because the maintenance costs are on par with cars that cost much more -- DEFINITELY higher than an M3's maintenance costs even outside of Ultimate Service. Caveat emptor.
Likely selling end of 2015:
11 M3 E92 Le Mans | Black Nov w/ Alum | 6MT | Premium 2 | Convenience | 19" | EDC | Prem Audio | Moonroof | BMW Apps | Yoko AD08 R | Vorshlag Adjustable Camber Plates | StopTech ST-60 380mm BBK | Castrol SRF Fluid | ModMyNav.com rear camera | ECS Tuning Sunglasses Holder