It's brilliant, nothing remotely like the eyetoy which is primative in comparison.
Having got one I can tell you it's way better and much more sophisticated than you imagine, Wii sports for example looks like a simple little demo of the remote but once you get into it it is amazingly complex, a subtle flick of the wrist for example makes all the difference during ten pin bowling.
However, what they do need to be carefull of is making games which try to use the controller when it doesn't need to. For example I have a racing game and the control system is difficult to use and doesn't add anything to the game.
But it is far from novelty in my opinion, everybody goes on about the future being vitrual reality, what's more real, pressing a button or swinging your arm when playing tennis. When it's done right on wii sports for example it's brilliant.