Well, that (and some missing FSX addons) clearly settle the question if I'll ever upgrade.
Once you "know" what to do, it's not much of a hassle. It boils down to what addons you want to try/buy and how they'll integrate with FSX.
Pretty much everything has been tested with SP1.
"Most" everything has been tested with SP2, but your mileage may very.
It seems that Acceleration has caused the most grief with addons; you'll need to do research on those. Your mileage will very.
Probably the best "how to" install link I've ever found is here:
http://www.simforums.com/forums/forum_posts.asp?TID=29041Please note before hand that the above link is best viewed using IE and not Firefox. There's additional info on some of the major addons that Firefox won't show...sheesh!
FSX is really a great sim and many addons for FSX are rendered much better than in FS9. I have both installed and use them both. Some FS9 files will work in FSX and visa versa, but not all that I like. That's why I fly both.
Hope this helps.
plug_nickel (Al)