I gave seedunlimited a try and I have not been disappointed.  Granted, I have nothing to compare it to, but it is the single reason I have managed to upload 253 GB in 4 weeks.  It could easily have been more, but I was not proactive enough.  (Is ratio-seeking behavior frowned upon? ).  Back to the merits:  The setup was prompt even though the website sets expectations low.  I would call it a "reseed box" however, because I think uploading original stuff would be a substantial challenge.  Perhaps my experience is unique, but ftp/sftp seemed unusually slow.  Likewise, uploading or downloading from the file manager was strangely sluggish.  I had no problem downloading over simple http via the "Downloads Folder" on the control panel.  (As for WebDAV … I would rather write down the 0's and 1's as someone read them to me via telephone than give that protocol another chance.)  With HTTP I max out around 6

None the less I am poking around for other options.  How do you know you have found the best until you have tried them all?