I don't have any seat time in the 997 GT3, but here's my opinion:
I think the 997 GT3 is going to be an awesome vehicle, but like most cars nowadays they are becoming less hardcore by the generation. Especially the US-spec ones...i.e. no cool CF seats and sunroof is standard.
That being said, I'm 100% sure that the 997 will be "better" than its predecessor (stock). It will definitely be faster, and I've heard it's easier to live with day-to-day (albeit that's not the point of the GT3).
I also think that it's aesthetically superior to the 996, but that's subjective.
I say get if it yo