I use four p2p programs to find things of interest. For my money, I like WinMX best because of its ability to successfully resume partially downloaded files from several sources with completely different file names.
But it sucks because virtually no one using this program has anything of interest to share.
From what I've been able able to observe, they're too busy chatting to get beyond sharing the obvious files.
Limewire, Kazaa and Emule suffer the same problem -- plenty of the obvious stuff, little of the rare/interesting stuff.
Which makes me wonder if:
1. most p2p users are "average joes" with mainstream tastes -- so little outside the envelope will ever be found.
2. something else is happening -- though I can't think of what right now.
For me, the bubble has burst no matter what anyone says as p2p file content seems to have ossified like AM radio -- too many hits and memories.
The reception is mostly good but the content sucks.

I think it might also depend on the skills of the user. I tend to find 'rare' material frequently. After a time you tend to pick up on ways of finding those rarer items. I can't comment on the other 3 apps, since I've only used 3 on the mac. One I retried recently called Myster. The network is a little larger than it was 3 years ago, but still suffers similar problems.

I've been downloading stuff for several years and consider myself to be quite good at hunting down rare stuff.
Rare stuff is harder to find than it was.
A test: try to find and download Tom Russell's Cuban Sandwich and/or Neville Marcano's Money Is King. It will be fruitless. Trust me I've tried for the past two months.

The best ever was the old Napster, after that AudioGalaxy was good to get the odd stuff, nowadays I think Soulseek is your best choice.

anyway here are some links:
http://www.zeropaid.com/php/filesharing.php

http://www.slyck.com/dictionary.php?letter=all

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