"It depends."

Take a read here:

http://lukazi.blogspot.com/2009/04/game-controller-atari-joysticks.html

There are different ways to adapt the digital-to-analog world of Atari-to-Apple controllers. And how games respond is going to differ as well. I think you're going to have to jump in and see if games you like respond the way you'd expect given the new inputs they're getting.