I'm thinking of getting a 360 controller for my PC and I was wondering if Chaos Theory would play the same as it does on an actual Xbox--I heard that it's still not as good.

Just the analogs don't work. You can use Pinnacle Game Profiler though for those, and Google a profile for Chaos Theory. Works just like the Xbox version.

This is what I've been doing for CT and it works very well. Map buttons directly from Xbox controls in the controls menu, but use Pinnacle only for triggers for fire/alt fire. Works beautifully, very smooth, and you have full movement speed control the way you should. To do the whole thing in Pinnacle would be a lot of trouble, but using the built in joystick controls menu you only need to map mouse buttons to triggers in Pinnacle.