The default bittorrent client in Ubuntu is Transmission. Some will argue that Deluge is a better choice. Quite some time ago I tried both and decided on Deluge. It seemed to be faster and seemed to use less system resources, allowing other programs to run concurrently. All that changed a few weeks ago when an update to Ubuntu broke Deluge. At this time it is not working, at least not working with Jaunty. I returned to Transmission.
Transmission works well at times and at other times it does not. Typical download speeds with Deluge started around 90 KB/s and often exceeded 200 KB/s. Sometimes Transmission will achieve similar speeds but it often gets stuck at speeds less than 30 KB/s. For any given torrent it does not connect to as many peers as does Deluge. I became very frustrated a few days ago while downloading a 700 MB movie. The seed/peer ration was good but Transmission was limping along at about 10 KB/s. It would have completed the downloaded eventually, but I wanted to watch the movie on that day and not the next. What else could I try?
I use the GNOME desktop environment. Now it’s a fact that many programs optimized for KDE will run with Gnome, perhaps loading a bit slower and not looking quite so good. A quick search turned up ktorrent as a candidate. Would ktorrent run with GNOME? I installed ktorrent from the Ubuntu repository. Then I downloaded the torrent seed file to my desktop. Ktorrent installed in the /usr/bin directory as I expected it would. A right-click on the torrent allowed me to choose ktorrent to open the file. Everything worked very nicely. In fact, configuring ktorrent to use the same download location that I had configured in Transmission enabled ktorrent to pick up the download where I had abandoned it! Ktorrent quickly attained download speeds of about 190 KB/s and in less than an hour my download was completed.
I look forward to the day that Deluge gets fixed. Meanwhile I have configured Firefox to use ktorrent as my bittorrent application. And by the way, it really doesn’t look too bad with GNOME.