If you get anything other then an Xbox360 controller for the PC, you will have only trouble, that's the truth.
The PS3 controller surely it's nice, but you can't go and remap everything with something like joy2key and expect it to work flawlessly.
Most PC games out there and surely most future games have a great implementation of xbox360 controller.
I mean control set up is already done and every button works as expected ( like the d-pad navigates menus, start is like enter etc...).
Any other controller will suck, because even though you manually setup the buttons, you still won't be able to use the controller to the fullest.
Another nice thing is that when you connect an xbox360 controller to the PC, the game recognizes it and displays the corresponding button on screen during tutorials and in menus.
Whether is a Logitec, or Sidewinder or whatever it will just suck.
LOL even if you remap the PS3 controller buttons with something like joy2key or xpadder on a game that already has gamepad support it will just conflict with the real controls and you won't be able to properly use the analogs.
The only valid solution is actually an application called xbox360 controller emulator, which basically tricks your games into thinking that you are using an xbox 360 controller instead of whatever you are using, but you will need to assign each button in the config file to the right value otherwise it's gonna be all screwed up. And it doesn't work with every game, there are several version of the emulator which fix compatibility with various games.
But once you get it running, it's fantastic in a sense that your PS3 controller will work very well and all the buttons correspond to their equivalent on the xbox360 controller.
I have a PS2 controller with an USB adapter and I play PC games like this, but it's always an headache to make each new game work with it.
So compatibility being what it is,plus a kind of difficult setup, it really is too much trouble to put up to when you could just get an xbox360 controller.