Shareaza

This filesharing client is, for lots of users, the P2P solution due to different factors, such as high speed and the support for four different networks: Gnutella, Gnutella2 (G2), eDonkey2000 and BitTorrent.

Shareza uses the power of the main 4 filesharing networks and takes the most out of the content of each network.

The search option is good enough and allows you to find any file, it supports multiuser download to speed up the process and it's important to say that it doesn't include any kind of advertising nor spyware.

You know it's difficult to decide the best P2P client and to choose one for you, but if you feel you have to change it, try shareaza and you won't be disappointed.