If it's physics you want for flying 3D or just plain real simulation go AFP.

From what I've read if you want to play a game with good graphics go get Unreal or Doom 3 or whatever. XTR=simulator? Well then I guess so does FMS. (Not bashing just my humble opinion)

And then I guess I have to say one good thing for G2. If you want to practise autorotations with helis then I think you want G2. That's the only thing I found it to be a little more fun than AFP. But AFP is right on its heels with that one. Sorry, I don't practise flying heli at all so I'm clicking on my AFP all the time.