Not to sure about stable yet. I'm still having issues with the automated domain backups [yeah I know, should be using psabackup, but hell this is easier and technically should work].
Backingup and storing locally seems ok, but backing up to an alternate FTP seems a little hit and miss. I have 10 domains on a daily backup; atleast 1 will fail, one night domain A will fail, next evening it will be domain E that fails. Cant figure it out.
The remote FTP is on the same domain range, and is only accessible from within the closed network (1&1 UK).