i use BackupPC (for pull situations) and storebackup/sshfs (for push) (both free), to any other server, or a VPS (eg tektonic, $15/mo).
the interesting part is regulating the bandwidth usage so other connections to the same servers don't get crushed to a crawl.
turns out a small few well chosen tc commands manage that quite well.  ask, and i'll tell.
-g