Almost always my movies even though i have tons of music, and always the most obscure shit. I have Disney movies and Breaking Bad, but people go for the auteur french sci-fi animated features.
Soulseek gives me much the same joy of sharing as torrent does, perhaps more so because it's one-on-one with a username instead of an IP.
It's very easy to contribute to Soulseek as opposed to torrent, you just mark your shared folders. I think there's probably more content as a result, at the cost of the inefficiency of multiple people offering the same thing. Which i'm not sure matters.
I don't know if the rooms are really worth it. You only get the messages starting when you logged in, so you can't catch up to what happened before; this problem is particularly relevant because most rooms are dead; those that aren't dead consist of a lot of vicious arguments; and it's live chat anyway, never my favorite format for discussion.
I prefer Soulseek to eMule just because it works, but i also found it simpler.
Unfortunately my VPN doesn't play well with Soulseek, apparently it doesn't support port forwarding? I'm not sure how to fix this. It may in fact have been a problem when torrenting too the whole time and i didn't notice.
Overall i really enjoy Soulseek and will probably always have it in the background, it's pretty great!