I had been using Tomato torrent, but I had a torrent that got most of the way downloaded, then locked up- and any time I'd try to re-open that torrent, after checking the existing download, Tomato had some error that would prevent any other application from launching on my computer, and I couldn't even restart- OSX was totally borked. This was repeatable. Anyway, I wasn't looking for another client, but thought maybe I could salvage that downloaded data and finish getting the torrent if I tried another client.

Well, I'm not going back. I did like Tomato, but Transmission has everything I ever wished Tomato had- one convenient window with all the info I need instead of windows all over the place, caps on total upload and download rather than just per torrent, a watch folder. It's even intelligent about checking existing downloads one at a time, which is faster than doing them all simultaneously and having the hard drive head zipping back and forth between files all over the place. It's great. I've experienced one small bug with it trying to notify me when a download was finished, but overall, it's great.