I've been itching to get one of these for a while now, so I finally broke down and ordered it. The best part is that you can "defish" the results in software (using the freeware PanoTools), getting you a fantastic rectilinear wide-angle lens as well.

You start with this (pardon my ugly office...):



Then, you end up with this:



I'm not sure which I'd call more distorted, but at least all the straight lines are straight...