I have had it for a few months. Make sure you go to
x-plane.org and get the update to 9.22 (or 9.21rc1).
It has its up & downs. I think in most places the scenery is not nearly as good as FSX + addons. The Xplane sim does run a WHOLE LOT SMOOTHER than FSX. I guess that's what a properly coded flight sim does.
Xplane has different flight dynamics, more "reactive", some think they're better than FSX and some don't. I think if you get a quality addon plane for FSX (like the Carenado Cessna 182RG) then the flight dynamics in FSX are just as good if not better...FSX seems to simulate plane mass & inertia better. With Xplane when a control input is made the reaction is instantaneous-wouldn't happen like that in real life in a 3000lb. plane.
Xplane scenery sucks IMO. There are some photoscenery addons available but FSX scenery rules over Xplane, especially with roads. And the aircraft exteriors are far better in FSX.
I think I am a devoted FSX fanboy. Xplane hase more work to do to win me over.
So there you have it-my opinion of Xplane.

-Jim