Three, four years ago Soulseek was THE online network to find and exchange music. Looking for some obscure, independent title, you name it, you'd find it on Soulseek. Now, with the likes of Last.fm, Deezer or Pandora, there's many more ways to find and listen to music online. Yet Soulseek remains an excellent P2P network to download tunes. While the Soulseek client is easy to download and run on PC, Mac users have it a bit tougher. You'll have to use an alternative client such as this one, SoulseeX.
The application allows you to view and manage your transfers, see other users that are connected and even chat about latest tunes or suggestions on what to download. SoulseeX is organized in a multi-windowed interface, which some users hate. I'd prefer everything to fit into one window, but still believe that the multi-window feel gives you more freedom to organize it on your screen.
In terms of performance, SoulseeX is known to be a big buggy and can crash every now and then. It does connect quickly to the Soulseek network though and is easy to install. The really worry with SoulseeX though is that it hasn't been updated since April 2006, meaning any bugs you have with your current version will remain.
Although a bit buggy and fitted with an awkward interface, this remains the best Soulseek client for Mac.