Bought one of these on a holiday to the States, brought it primarily as a speaker for my ipod (for which it does work surprisingly well, quite a loud and clear speaker given the ifish's size).
Got quite a surprise when i realised all the other things it does, and decided that it was best placed in my office at work where it entertains the crowds (plugged in to the ipod or otherwise).
My only wish would be for the ipod to be able to be placed directly on or in the ifish so that it could still spin around freely - as it is, you hook up an ipod (or any external audio device) via the supplied lead which goes into a fin. The ifish still does its thing, but never spins 360 degrees (it knows not to get in a tangle with the lead).
Overall a fun device, not the most useful gadget ever, but lots of fun.