I'm interested in a belt drive, too, but mainly because I hate getting a greasy chain stamp on my leg. :P Belt drives don't need lube, so they stay pretty clean.
I'm surprised there are retrofit kits. With a belt drive, usually one of the chain stays has a gap in it so you can get the belt on and off (you accomplish the same with a chain by taking a link out to install/remove the chain, but this is not an option with a belt).