There are actually three versions, the "original" 100, the 100A and the 100B.
Basicaly, the B is newer than the A, and has a couple more options, but all in all, they're fairly similar cameras. It's sort of the same as Canon's GL1/GL2 cameras. Very similar bodies, same CCD panel, same lens, just a couple product improvements.
If you ca't afford the newer 100B, a 100A will be very similar.
But again, I don't actually own these cameras, I've just read about them. If an owner is around here, they might know better than I do. :)