I'd recommend trying it before you bash it. I've tried it on several occasions in the past (and now own it) and it's accuracy/lag do not feel significantly worse than the wii. I've seen zero problems with lighting, clothing, etc. The voice recognition is actually quite excellent and it even works reasonably well while a video is playing.
The required distance from the device is annoying though. The menu system as well, but thats a software problem and can be fixed. Check out the dance game for a great example of an intuitive menu.
Even if it fails as a gaming device (which I doubt), I still see the ability to control your entertainment system without a remote as being common place in the future. For example, I was watching a movie on my xbox while I was reading slashdot. When I wanted to concentrate on replying to a post, I just said "xbox pause" without my fingers every leaving my computer. In fact, I hope the kinect is a finanicial success, because that will inspire competitors to emulate and improve the experience, which means even more awesome stuff for consumers.
xbox play...