Check out these two videos comparing the physics of AFP and XTR

http://63.246.139.60/reflex.wmv

http://63.246.139.60/ikarus.wmv

No flames intended, but AFP is a class above. Here are comments from the professional pilot who made the videos :

- AFP was the sweet honey right out of the box of the four SIMs. It flies like a light, stable, big plane right out the gate. And, I like it for IMAC too because it responds like an unloaded plane when you unload it (in the snaps). I think this is the SIM that is most likely to please the guy that only wants to buy one SIM. Let me say that if I was trying to learn 3D maneuvers... there is no doubt that I'd get AFP and would probably be none too keen on XTR.

- On to Reflex XTR...The planes are alot harder to fly out of the box They're kinda harder to fly at all times.

FWIW