Well, I just picked the game up yesterday...I am enjoying it so far, but it has definately taken me a bit to get used to. The button combinations for the other moves are what gets me - do people actually memorize all 60+ moves for each player (granted many of the combinations are shared between players)? If I could just zap all of those moves and combos into my memory I would be having a lot more fun with it, but I will probably never ever use most of the moves. I haven't played it with anything but the Wii Remote yet, and I find that generally the motion controls are responsive. It says in the book that your motions need to be about 12", and as long I keep that in mind and don't try to do quick, small movements, it seems fine.
One thing that is frustrating me is the Kreate a Fatality...it's much more fun to just push a single combination and watch the fatality, and I find it a bit ridiculous that you have to guess which motion to do next. Having to do them to on-screen cues would have been fine, but when I want to pull off a kick-@$$ finisher and I can only get two gestures figured out, it's really anti-climactic.