tixati is a cross platform (Linux, windows) torrent client with some good features. I am especially impressed with it's automatic bandwidth limiter (uTP). Also allows you to categorize torrents and manage transfers efficiently. It also provides deb packages and standalone executables and can run in portable mode. It lacks few features like remote control API and WebUI. But these things are in development queue. It looks promising and could become de facto BitTorrent client.
Download tixati from following link.