Having had both 997 & 991 GT3s, the 991 certainly has the true spirit of a GT3. It is a GT3. I like it far more than the 997. However, my friend who has my old 997 GT3 disagrees with me completely
I grew up on manual cars, and still prefer them in general for the fun experience they offer.
I had both generations in my current stable, I'm not sure which one I'd drive more. But I will say the 991 is certainly more capable, and the 9k redline brings a whole new element of fun to the driving experience (metzger or not)! Not to mention I'm FAR faster on track.
Being smoked by a Nissan GT-R on track in the 997 GT3 was no fun... no longer a concern in the 991. And yes, faster does = more fun on track in this particular case.
All that being said, I certainly would love to have a 911 R! Begging the dealers currently...