Switch source if download drops below xx kB/s
I'm guessing it won't be very hard to implement, since the "no new downloads if speed exceeds xx kB/s" already exists, and is working flawless.
Too often my experience is that you search for a file, find 20 sources, and it always starts downloading from the slowest one
Maybe even an option to remember deprecated users... ie. if there's an 56k user that has everything you search for, he will always be one of the sources in your queue... sort of a user-blacklist.. damn annoying 56ker's