And it costs $30+.
True, and it is licensed per machine too (though subsequent copies are at a steep discount).
I use it for some things that wouldn't work on just rsync, so I enjoy it. Also, easier to configure and maintain than a bunch of vbscripts and whatnot, and easily cross-platform* (and handles SFTP and Google Drive and other stuff too).
The file monitoring options are nice, too. You can set it up to work like your "private Dropbox" using your own storage (where the syncs happen within seconds of the files changing). I'm now syncing my media drive backups from home to the office automatically, in the background (and that's now around 6TB all things told). I just "started it off" by syncing locally, and now it keeps changes up to date easily via the Internet.
So... Works for me.
* Not that rsync isn't. Windows would be the "hardest", if you wanna call it that. But your scripts might have to be written in different environments, so there's that.