Been a really long time since I used it, but I remember it being a big pain, and for the most part, found that it wasn't worth the effort. All of the things I needed from DC were much more easily obtained from Usenet or Bittorrent.
As was my experience with it. I found it to be extremely difficult to use, and difficult for a lot of other people.
If you think about it, a P2P network that's so hard to use that it prevents people from using it is the definition of worthless.