BlackMUD has been around since the beginning of almost any mud, and to this date has an average on peak times of at least 15-20 people. Immortals are always active, quests happen often and there is an option feature to keep you out of player-killing, or get you into it.

Great gear, a roleplaying environment and 50 levels, plus remortal classes . I could go on but you'd probably get a better view for yourself if you would try it out. It's well worth it as I've been a dedicated player for 6 years.