Could you or someone explain why these fantastic sounding tools don't get a developed front-end? Or if they do why am I missing them?
The best solution I've found is ChronoSync.
For duplicity, there is a quite good ui in the form of deja dup (see http://www.howtogeek.com/108869/how-to-back-up-ubuntu-the-ea...). It's really nice and easy to use, and if I recall correctly it's installed by default on Ubuntu.
Moreover, many of these backup tools run on servers (or as an automated background process) where a graphical interface is more of a handicap than an asset.
I think that in open-source software "pretty interface" sounds often like "customer-oriented" which in turn sounds like "getting paid".
There are currently multiple interfaces available to bup, but each one has some quirks. bup's web interface is still very embryonic and would need the magic touch of some designers / integration specialists to make it fun to work with.