I'd love the ability to set background transfer settings on a per-server basis.
For example - when moving files from my server in the next room, I only want one file running at a time. However, when moving files from my other server on the opposite side of the world, I want 8 files at any one time running. This is because my ISP, for whatever reason, seems to only allow 100KBps per connection - so one file at a time gets my ~100KBps, while 8 at a time gets me ~800KBps.
These limitations obviously don't apply within my home network, hence the need to set transfer settings on a per-server basis.
Thanks for a great application though - at the moment I just manually change the background transfer settings each time I switch server!