uTorrent is the most popular BitTorrent client in the world .and it is widely used by most of the people . It includes great features like scheduling , bandwidth prioritization , auto downloading etc. uTorrent also supports the Protocol Encryption with other clients like Azureus , CometBird , BitComet etc . And it also supports peer to peer exchange with other clients .  uTorrent is the super fast torrent client and covers very little virtual memory of your computer . And the program is very small  ( 539 Kb ) but have great features .