I haven't actually tried X-Plane - I'm going off what I've read and others have told me. Truth be told - I barely find enough time to play with FS2004, yet alone dedicate time to learn another sim. I do feel a little guilt at making Bill Gates a little richer...
However, the number of users of FS mean you will probably find the add-on aircraft and scenery you want. And despite its deficiency I find it accurate enough for me (PPL holder)
The comment above about 'sufficiently speedy computer' is interesting too -- my eMac cost me around $1800 new and it runs x-plane very well. A very modest hardware overhead!
Doesn't HAVE to be the 3ghz P4 - I meant don't get the sh*ts when it doesn't run on your Pentium 166
I'm running a mid spec AMD Athlon (<$800 (no monitor etc))