I have been reading this thread and its very interesting. No mention of MySQL backups and restore though! We are looking at Percona Extrabackup for this. In testing a 9.6GB MySQL database took 3 minutes to dump and 4 minutes to restore. Using MySQL dump was 30 mins to dump and just over two hours to restore.
We did have an issue with the IBData1 file becoming to large so we do need to give this some more attention before we decide to go with this solution.
For me it has to be rsync as Duplicity is still in Beta form and is very unlikely to be allowed to be used in a medium to large organisation. We for instance have to justify all technologies used whenever we need to introduce something new.