I'm really not sure. I think it will do okay in US if they assimilate it to some key titles, but I really don't know. The damn thing is so hard to judge. If I look at past EyeToy performance as evidence then I say it'll make no difference to market, if I look at Wii then it might.
This one I'm just going to wait and see what happens rather than guess.
Try to be reasonable... its easier than you think...