I still have a Space Orb controller which is based on that. Support for it was pretty well abandonned which is too bad. It took a bit to get used to, but it improved my (relatively meager) FPS performance fairly significantly. The ball doesn't really move much so you have to get used to just applying the pressure needed and not expecting any real motion feedback. It's also a little unique in that it came out as a serial device at a time when most game controllers used the game port. This made it laptop friendly as well.
As I recall, there was a big conroversy when it came out because it had a button that could be used to do an instant 180 degree flip in a space shooter I can't remember the name of now. That move couldn't be done with ANY other controller at the time so if you were playing online, it gave you a fairly major advantage. You'd get somebody on your tail, hit the button and blast them without having to find a place with room to actually turn and face them. Other controllers soon came out with the ability to do that needless to say and much of the whining about 'cheating' died down.