uTorrent is the result of trying to keep this tiny Bit Torrent client small while adding several new features and working on the product under the hood. It is a free, but ad-supported torrent client application that's attractive, light on system resources, well-designed, comprehensive, easy-to-use and reliable.
Here are some screenshots to illustrate the features and user interface of this application:
BitTorrent
qBittorrent
qBittorrent Portable
Tixati
Tribler