If you do try out Arm, keep in mind it's more like... an IC D&D MMO than a roleplaying MUSH. If you've played an RPI, that's what you're going to get - it is one. The RP is going to be pretty fast-paced and combat can pretty brutally lethal. If you end up in any kind of PVP, it becomes twitch reflexes. You can die in some very stupid ways as well.
I played it for about 12~ years off and on. I don't think it'll really appeal to most of the crowd here, but if you're okay with the above caveats and up for trying something new, it's worth a shot.