qBittorrent can now be considered as a good alternative to other bittorrent clients. It provides a lot of features such as:

* A polished Graphical User Interface written with Qt4 toolkit
* UPnP / NAT-PMP port forwarding support
* Encryption support (compatible with Azureus)
* Multiple simultaneous downloads / uploads
* Download from RSS streams
* An integrated search engine
* DHT (trackerless) support
* uTorrent Peer eXchange support (PeX)
* Directory scanning with automated download of torrents inside

And many more. See website for details.