Full disclosure: I'm an actual licensed commercial pilot in Canada. I have about 15 hours of sim time in my logbook, 12 of which were on a commercial and Transport Canada-approved version of X-Plane (the other 3 were on Prepar3D, a version of FSX), and 10 of which applied to my license.
This is a simulator, not a game. You can mess around with the fun fighters and experimental planes, but this is first and foremost a simulator. And what a simulator!
If you're like me, you find fun in a challenging radionav approach. You find fun in managing system failures. You find fun in printing out checklists and having them next to you while handling the simulator. You find fun in education and a job well done. And this is where you get it. You can tweak the simulation accuracy, you can go from messing around doing aerobatics in a fictional plane, or you can turn your garage into a full-sized flight simulator. You can do all this in X-Plane 10, and it has the added bonuses of being more accurate, prettier, and less system-taxing than FSX.
FSX is almost a decade old by now, is a RAM hog, hates graphics cards, is 32-bit, and is still slow and unoptimized. On my machine, it runs terribly. But X-Plane 10 has a 64-bit and 32-bit executable, supports multi-threading, is considerate of your RAM, and looks fantastic.
I spent hundreds of hours with FS2004, FSX, and X-Plane 9. Thanks to them, my instrument and radionavigation training was easy. Thanks to them, I passed the infamous INRAT on my first try. This is a fantastic simulator, simply the best on the market, and the only one worth your money. I can fully recommend this for full price, and I'm a pennypincher.