I use java moss in my tank, just because I could buy it at a local retail store verses having it shipped to me. Instant gratification I guess, and if you don't know, java moss is quite common.
Anyway, it's very easy to grow and cover the bottom of a tank with. As for other mosses, dunno, but I suspect that they're all about the same... it's like slightly up the evolutionary chain from algae, heh.
Personally, I'd stick to rosettes and stem plants for the substrate's surface, and keep the moss attached to objects like stones and driftwood.