Transmission is designed for easy, powerful use. Transmission has the features you want from a BitTorrent client: encryption, a web interface, peer exchange, magnet links, DHT, µTP, UPnP and NAT-PMP port forwarding, webseed support, watch directories, tracker editing, global and per-torrent speed limits, and more.
Please make note of the size of the "downloads" volume, which is pre-set at 10GB. You may need to resize this depending on your needs!