I just keep downloads of the torrent nature to my PVR server that runs Windows. I don't think I'll ever need to run anything but µTorrent. I can't see how anyone else can do it any better without creating an entirely too bloated app - like Vuze (which is also available for Mac OS). In my limited testing, µTorrent under Windows was also faster than Vuze and Bitrocket in Mac OS.

BTW, older versions of Transmission may give you problems with some trackers that ban an assortment of version numbers. More than likely to be private-type trackers though. Don't know if other clients will have any type of connection preference though.