Tell you what, I'd take a new GT-R anyday. Fuck all the haters.
People hate because they know they want one secretly deep down.
Of course, I'd be just as happy (or happier) with the Viper...
Edit: However, let me say this. Seeing a GT-R in person doesn't make me go "OMG Look!" because let's face it, I can walk right into a Nissan dealership, give them the money for a GT-R (if I had it of course), and drive off in it. The Viper, might be a little harder to acquire.
Jay Leno said it best "I'd rather drive a slow car fast, then drive a fast car faster."