This is interesting; a gamepad level 50 Halo player approaching the xim

Do you have previous experience with m&k?
The XFPS alone, is in my humble opinion a piece of crap. I have the XFPS Sniper (the green one) and playing with it really has very little in common with what I'm used to on the PC. Especially in halo you see its limits, and a gamepad is much better.
I suggest you to wait the a couple of weeks. XIM2 will be out soon, and it would make little sense to test the XIM1 (which in halo, although the xim is atm the best m&k device, is not that great).
cheers,
meme