X-Plane has the most accurate flight model. Condor as mentioned above is a glider sim and not a true Flight game like this. I question its flight model as well, though maybe someone can show me how it is superior to the X-Plane version?
X-Plane uses the NASA models of airflow over surfaces, so frame rate is important. If you frame rate drops into the teens, you might default over to a dumbed down flight model, so never expect graphics to be on par with FSX. FSX uses pretty scenery and a dumb flight model, but does well in the cockpit dept.
So it depends on what you want. If you want to tinker with aircraft to see if something would actually fly in real life, X-Plane is it. You can build any weird design you want, and it will fly like it is made - or not fly that is.
X-Plane also simulates space. It also has Mars for low atmosphere flight and low gravity flight.
FSX can get chunky though in the FPS area. It is artificially boosted in FPS for DX10 (MS is purposefully degrading performance on XP, but that's another matter), so if you have Vista, it will run better. If you have XP, stay away. Notice how every other game on the planet runs faster on XP? That is your first clue.
I get FSX for almost free. Frankly, I'll stick to my X-Plane and pay full price for it.
-S
PS. Go fly a Cessna already. It won't cost you much. Any small airport will take you for a check ride and teach you the basics for almost no $$$.
__________________
 
|