Well, I have a PS2 eyetoy, and I'd say it's pretty fun when it works, but the conditions to do so are limited. Using standrad incandescent lighting, it's typically not good enough to get the edges of the screen - if I adjust sensitivity, then the whole screen has random jitters, and can cause any part to activate. Also, the colours of my walls are apparently too close to my skin colour, and i have to wear gloves to play properly.
will they sort this kind of thing out for PS3?
Somehow, I doubt it'd ever get to the point of being absolutely great in all conditions, seeign as it still uses the technology of colour moving on colour. If it could actually recognise faces, and shapes, then yeah, maybe cool then.