Hello, I'm currently using KTorrent4 which comes with KDE for me, and wonder what of those features OneSwarm support.
There is a list of some interesting KTorrent features from wikipedia:
Support for UDP trackers.
IP address blocklist plugin
Port forwarding with UPnP (Universal Plug and Play)
DHT (mainline version), and support for trackerless torrents
µTorrent peer exchange (PEX) support
Ability to import partially downloaded files
Directory scanner to automatically watch directories for new torrents
Manual addition of trackers to torrents
SOCKS v4 and v5 support
Generation and parsing of magnet links
UDP tracker scraping
I'm also interested how much good NAT traversal algorithms does OneSwarm have, while it is not problem in my case, in order to recommend it I believe it should have a good bunch of them.