My cousin has a house bunny, and she's just a doll! She's quite agressive with the cat though, and they have to watch out for that. Litter training was no problem and she's fine. Only thing is keep a watch on them while you're cleaning the tray out, as they will go in the same spot whether the tray is there or not! She is hilarious though, because in the evenings, she lays out flat, front and back legs out straight, right in front of the telly!
One thing about house bunnies, electric cables. The current is higher here and in the UK than the US, and I had a friend a few years back that had a house bunny who chewed an electric cable and not only blew up the telly, but electricuted himself. Something to be aware of.
Good luck!
K