Product review (5 stars): but it's been great so far
My kitchen refrigerator doesn't make much ice, but we host a lot of weekend parties which is why I bought this.  I haven't had it too long, but it's been great so far.  You pour water into a reservoir below the ice tray.  The water gets suctioned up into an upper chamber, where metal rods drop into the pool.  Ice forms around the the rods.  After a bit, it releases the water the water back into the pool and then drops the ice into the ice bucket and it repeats the process.  It seems to take longer when you first turn it on, presumably because it's reusing water that it's continually cooling.  If you leave it on for a long time, the ice will slowly melt back into the pool and more ice will be made.  The ice tray area is insulated but not refrigerated.  The ice cubes are pretty big, but because of the hole in the middle it doesn't really last as long as you would expect.

I only use it for a day at a time and have only had it for a couple months, so I can't speak for the longevity of the device.  My friends fill big 32oz glasses with ice for their drinks to the top.  Between this and my normal refrigerator, I think I'm finally keeping up with them.