Personally, I've had FS9 since it came out. I loved it then, when I was running it on a P2-400 I had Dell built just for it (for about $5,000.00, as i recall). I've been transferring it from PC to PC as I upgraded, with my wife's Dell 7400 one of the best, till the HD crashed. I stuck it on my brand new Dell (yeah yeah, but they've done good by me. My wife was deep in the 7200 scandal they had, so this 1750 laptop was pretty much free, and it travels. The 7400 weighs in at a bit over 70 LBS! :D ) and it's been happily zipping along ever since. Eventually, I discovered the world of add-ons a couple years ago, whether scenery, or aircraft, or whatever, as well as the forums, and it really took off. No pun intended.
I picked up FSX-SE, when it was the incredibly high price of $5.00, just to see what all the FSX fuss was over. I never did, so I still FS9 mostly. I did kinda go add-on crazy for FSX when I first got it, but it got kinda old pretty fast. Besides, this poor old laptop can't handle much in the way of add-ons anyway. Not for FSX-SE at least, altho I've never had it crash on me, I must admit. Of late, I must also admit, I've been kinda focused on this FSXBA Hornet project I'm sort-of helping out on, a little. We're making pretty long strides, too, I have to admit, and the thing is treat to fly. As near as I can tell, having studied assiduously the NATOPS, the flight characteristics, as well as hardware realism, is getting pretty darn good. I'm still trying to figure out some maneuvers, but I can land 8 times of 10 (3/10 on a carrier). For me, It's a lot of fun. I was too stupid (read foolish. Plenty brain-smart) to go to college on my parent's dime to go the officer route and fly myself, sadly, so this is the best I can do, now. So, I do!
Anyway, other than that, I'm FS9 all the way, including a Hornet on it from Team FS KBT, and Dino's famous F-14D, which I love. Both slightly (ahem) modified, of course. For me, this sim is an ongoing learning experience, and I love every second of it. The details of making a decent Panel.cfg, not always very "true to reality", the "Hey, it worked!" of an aircraft.cfg, or the "so THAT'S what that does!" of an .air file, are always a bit of a thrill.
So, short answer, I guess, is FS9, 85%, FSX-SE, 15%.
Pat☺