I've been using it for 3 months now... Hell, its the BEST p2p client for music for me.... but its a community, try to chat with people there too, they'll allow access to people in their user-list (i.e., friends)... I'm met lot of cool people there, and its easy to find people with your musical taste..
Though you can find any other files (movies, vidz,etc) i wouldnt recommend it unless you have a fast connection, coz you can download a certain file only one at a time from a person...(for eg., if you download file x from user Y, you can download only x and nothing else from Y at that particular time (though you can download stuff from someone else at the same time))
i.e., you can download multiple files at once from many users, but only one file per user..
As far as mp3z are concerned, it ROCKS... you can also find rare stuff there... and the best part is... NO FAKE FILES.... which is why i've quit Limewire and used Soulseek for a long time..
Only one problem, if you PC crashes, thereby crashing Soulseek, the list of stuff you've queued up will revert to the old saved list.... so its better you disconnect Soulseek and reconnect it once in a while....
P.S.- I never understood what "alternative" music meant....
if you want mp3s, Soulseek has got 'em all of all genres...