AmazinGoods: uTorrent for Mac

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uTorrent is a free BitTorrent client, the Mac version (officially still in beta) of the popular, open-source uTorrent client for Windows. Much like the lightweight uTorrent for Windows (also weighing in at less than 5MB), this version of uTorrent excels at downloading files quickly with minimal resource overhead. Even more stripped down than the Windows version, uTorrent for Mac gives you a familiar, three-pane interface, with support for multiple downloads and probably more drill-down details than you even need--including graphs, tables, and other specifics on seed, peers, pieces, and more. You can also throttle upload and download rates, and stop seeding automatically at a certain ratio. uTorrent is probably not the best client for actually finding torrents (there's just a simple search bar that takes you to results pages in your browser), and users looking for browsing and viewing features should check out more full-featured BitTorrent clients. If you don't need a lot of extra features and you're looking for a fast BitTorrent client that requires almost no configuration, uTorrent is a solid option.

From BitTorrent:

uTorrent is the world's most popular BitTorrent client, and is now available for Mac. uTorrent Mac introduces uTP, a new lightweight BitTorrent protocol that makes incredibly efficient use of network bandwidth while reducing network problems. uTorrent also supports the Protocol Encryption joint specification (compatible with Azureus 2.4.0.0 and above, BitComet 0.63 and above) and peer exchange. uTorrent was written with efficiency in mind. Unlike many torrent clients, it does not hog valuable system resources - typically using less than 6MB of memory, allowing you to use the computer as if it weren't there at all.

Native Cocoa Mac client
Lightweight and Fast
Multiple simultaneous downloads
Protocol encryption
Peer-exchange
Trackerless support (Mainline DHT)