I have been using rdiff-backup for a few months, and have already lost
all increments for several times. Either because there's not enough
space, and rdiff-backup is not able to remove old increments without
lots of empty space, either because some file system corruption
destroyed some files from which rdiff-backup cannot recover anymore at
all, etc... And in case of (sometimes trivial) problems, rdiff-backup
never gives clear human readable error messages, but crashes with an
uncatched python exception including backtrace.
Although rdiff-backup has a great feature set, unfortunately I am
planning to migrate to some other backup system. I cannot trust a
backup system which fails so easily and takes all increments with it.