Swmud, or star wars mud, is a good mud in most aspects. It has a real feel of the starwars universe, full of many races, plants, and guilds. The mud even has a fully operational space system, where you can pilot the shuttle, fighter, freighter, or captital ship of your choice, convenience, or design. Generally the mud is pretty newbie friendly.
One of the best aspects of the mud is it's player killing system. Though not mandatory, the system is used by a good number of the mudders. After adding in the aspect of clans, alignment based battles, and the occasional backstabbing, you're assured a fast-paced experience, full of actual decisions, rather than 2 players sitting in a room, and waiting to see who dies first.
Downsides to the mud would be the lack of role-play. A few players have tried to bring some aspect of RP to this mud, but are generally ignored or ridiculed. Another problem is the status of becoming a high mortal. This achievement can only be done after reaching certain levels, and completing a complex quest. The problem being that this quest hasn't been fully active in the last year or so. This tends to keep player killing out of balance, as a large number of people have no chance of attaining the same advantages of their enemies.
All in all, it's a fun mud if you're looking for a standard hack/slash mud, filled with the delight, mystery, and wonderful feeling of the star wars universe.