We occasionally get questions from clients about using some file sync tool or another for their backups, and we are very firm with them: file sync is not a backup.

It looks like your software protects to some extent against accidental deletions of files, which puts it far ahead of most file sync tools. But, if it's still possible to accidentally delete the contents of a file or otherwise corrupt it, then it's not a backup.

We usually end up recommending Acronis TrueImage, which is in the same price range as your software. I'd happily recommend your software instead, since TrueImage is clunky and slow, but without archiving it doesn't count as backup software.

(For one real-world example: we had a corporate client get hit by Cryptolocker. It looks like in this case your software would've automatically copied the changed files over to the backup directory; is this the case, or am I missing something?)