I used Pueblo for a while back in the day but I always came back to plain 'ol telnet (Linux client).
I think this is one reasons MUDs have languished a bit though (at least for me).
I am writing a new MUD written in NodeJS (websockets + html goodness). It is very LP-inspired, though (hot updates, online content creation and decent editor [Microsoft monaco], efun names and applies similar to MudOS/FluffOS, etc). I'll publish it on github or elsewhere when it's a bit more usable (I briefly connected it to Intermud3 as "Emerald MUD Beta").