sorry for the lack of updates guys... i was in new york for a trip over the holidays and just recently started another quarter at my college. but heres some feedback for those that wanna know how the adaptor actually performs.
at the moment, im quite pleased with the responsiveness the adaptor provides, but as you can see from my original post, im a fan of fighting games. i was really disappointed about soul calibur 2 not working... ive tried all the different digital/analog modes, and none seem to work with the game.
one thing ive noticed, is that the adaptor seems a little buggy in the fact that it doesnt always work when you start up your xbox. sometimes, all the controls will be unresponsive upon startup, or other instances, only 2nd player works. a quick restart of the console can remedy the problem though. another thing i noticed is that in rare cases, the directional controls become unresponsive out of nowhere while you are playing. ex: i was playing marvel vs capcom 2, and after about an hour for some reason i wasnt able to move my character, but could still use attacks.
for marvel vs capcom 2 and capcom vs snk 2 EO, the lack of L and R triggers dont affect the game. you can easily config the controller layout in-game. however, if youre not a big fan of fighters, and want to play some other arcade-friendly games, there are a LOT of games on the x-box that require the L and R buttons, and you will be unable to play them. one game for example, is Sega Soccer Slam. the L and R triggers are required, and you cant re-assign them to the black and white buttons. another game with the same problem is Burnout 3

i hope i answered a lot of questions you might have, feel free to ask about anything else you want to know about the adaptor.
one last thing, feel free to post a game or list of games you'd like me to test =)