Synbak not only makes it easy to use the cool features of rsync, it also extends it's abilities. Synbak is easy to install, configure, use and maintain. Add the reporting features (web and/or email) and this makes a powerful backup solution. 10 minutes after downloading it we performed the first backup successfully.
Some of the features we like:
1) Error checking is well implemented.
2) Synbak creates industry standard backups that require no special programs or dependencies to view or restore.
3) The reporting options via email and/or web page make it easy to keep track of what is going on.
4) The configuration is straight forward via a well commented .conf file. For different backup jobs, just create another .conf file.
5) The ability to tell old backups to be automatically deleted after n backups makes maintenance easy.
6) The author is open to answering questions and very helpful.
As for down sides we have not found any. We have been using it for a few months now.