With ChronoSync can sync or do a backup for most devices and directories, and all that can be connected to the Mac, including a folder on your Mac, other Macs, PCs and external drives.

Possibilities:
• Fully customizable toolbar
• All settings are stored in separate files that can be edited at any time
• Synchronization in two directions
• drafting rules to filter the files by various attributes
• Compare files before sync
• Run a test to verify the results of synchronization before performing operations
• history of synchronization, which can be printed or saved to a file
• Automatic synchronization on a schedule
• Use AppleScripts to automate synchronization.