I've been using Dediseedbox for several months now. I don't get the best of storage space (400GB, I think) but it's only $15USD a month and I can get killer speeds, depending on seeder/leecher connections.
It's an entirely web interface to your box (utorrent) and you ftp to bring stuff home. The box itself has gone as high as several MB/s on several torrents simultaneously (and in both directions, but again, it depends on the speed of who is connecting).
My home connection isn't the greatest but I've gone close to 4MB/s downloading from the box myself via ftp. Usually it's around 1.3MB/s but again my connection isn't that great.
Overall, I like the service. My ratios remain high, and no prying eyes are connecting directly to my PC. I haven't really noticed any down time either. Once it was acting weird, but I logged into my account and sent the box a reset command. Simple. Problem solved.