There are some spam around yes. Just need to beware of these.

As for why a download can be slow can be various reasons. For a start, you are downloading from others like yourself, not from a site. So if the other person(s) have dial up or have lots of others uploading from them then their share of their own upload bandwidth to you may be small.

As with any gnutella client, re-search for the song to see if you get more results & more people to download from.

I'm curious to know which version of BearShare you are using.