TL;DR (at least not the entire thread)
If you go with Rsync you may find incron an useful add-on as well as with it you can monitor a variety of events on any given file or directory, like OPEN_READ, CREATE, CLOSE, CLOSE_WRITE, etc - and this way backup your data in real time whenever a condition applies.
Also if you will be rsyncing from one computer to another (in contrast to an attached storage) setting up an Rsync daemon on destination will make the sync to be faster and lighter than syncing over ssh; of course that if you need an encrypted connection between the two nodes you will likely be rsyncing over ssh. But again, if you trust your network, the Rsync daemon option will use much less resources.
Also should you go with Rsync, setting up xinetd may be even a better option than having an Rsync daemon constantly running in your target server.
HTH.