Well this is related to more IT than BIM, but I am a huge fan of SuperFlexible Synchronizer.  Tobias has written an excellent Synching software that I have been using for a long time.  It has a lot of advanced options. It works great for Backups to external drives, network drives or backing up remote locations. For remote locations and remote servers you can use DFS or WAFS (expensive) software, but for only $60 Pro version or $35 for Standard version you can get tremendous power over synchronizations.  It has both MAC and Windows versions available.

My favorite features:

• Inclusion/Exclusion masks (can help tremndously not to backup tmp/backup files)
• Partial-file updating
• Email notifications (Highly customizable)
•  Tree based Preview of what to backup (I bugged him to add this feature and he finally did, thanks)
• Run Script before/after
• FTP Syncs
• Realtime syncs
• Powerful scheduling
• Smart-Tracking (detects my moved/renamed files)
• Versioning (save overwritten files)
• Constant updating of the program to remove bugs

And the most important thing I like about it is that he is VERY quick to respond to support requests, open to suggestions and fixes bugs constantly