There are several things that make X-Plane very good.
1. All airports, fixes including STARS & SIDS can be updated every cycle from Navigraph (payware). Try and do that FSX, FS9 or P3D - This way your frequencies, etc are always up to date.
2. For the best performance you will need a graphics card with a min of 2Gb however 4 Gb is better and 16Gb of Ram. With this setup I dconstantly see 45-80fps.
3, If it crashes you only have to go the the log.txt file, scroll down to the bottom of it and you will see the cause. Try and do that FSX, FS9 or P3D . Here is an example, that happened after loading in some new scenery. I removed the bad nav file and everything was ok.
1:48:16.926 I/SCN: Failed to find resource 'test/AGtrees_test.for' (parent = 'Resources/default scenery/airport scenery/Common_Elements/Misc_Buildings/' at 'Resources/default scenery/airport scenery/Common_Elements/Misc_Buildings/test/AGtrees_test.for'
1:48:16.926 I/SCN: Failed to find resource 'test/AGtrees_test.for' (parent = 'Resources/default scenery/airport scenery/Common_Elements/Misc_Buildings/' at 'Resources/default scenery/airport scenery/custom objects/test/AGtrees_test.for'
1:48:16.926 I/SCN: DSF load time: 228467 for file Custom Scenery/Global Airports/Earth nav data/+30-110/+37-109.dsf (0 tris)
1:48:19.185 I/SCN: DSF load time: 2153799 for file Global Scenery/X-Plane 10 Global Scenery/Earth nav data/+30-110/+37-109.dsf (195817 tris)
1:48:22.388 I/SCN: DSF load time: 2786208 for file Global Scenery/X-Plane 10 Global Scenery/Earth nav data/+30-110/+38-109.dsf (215337 tris)
--=={This application has crashed!}==--