As you know X-Plane and FSX are very different simulators and some people like them for very different reasons. There are some positives about both and negatives as well. X-Plane is not without it's bugs and even with version 10 you have to plan on tweaking. I wasn't happy when I ran X-Plane with the default settings. People here helped me tweak that and soon I had great things happening and was having a lot of fun.
There is no reason you can't enjoy having favorite planes in both simulators. The most important part is stay open to the idea that you can have a lot of fun with it, but we can't think of it in terms of FSX. Definitely it's own breed of simulator.
A you may know there are major changes between version 9 and the latest version 10. So if you do venture back into X-Plane 10 please let us know any new tweaks and tricks you discover along the way and post us some photos of what your playing with in X-Plane.