mine seems to work fine. Ive been using it like this, but I havent really played much other that poker. Not sure if there is slight lag that might be an issue on FPS's (Ive read that there is...)
Is there some reason to do this or is it just to save an input on your TV? I'd guess you haven't gotten many responses because most have not/will not use it. I personally don't see the point in forcing yourself to turn on two consoles just to play the 360.