Thanks to Rui at the Tao of Mac – I was turned on to Unison to replace the volumes of rsync functions I use on various servers.
Unison synchronizes rather than mirroring as rsync does – making it valuable for workstations as well as development and production servers. To boot – it works on OS X!
The app, found here, can track two directories on two separate systems, or on two hard drives on the same system. It processes updates to both replicas in a bi-directional fashion rather than simply backing up or copying data from one side to the other. It can additionally work across platforms – so Windows can be synched with Unix and so on. Very nice.
It has config options for working with Subversion among others – which I finally have switched to from the crusty old CVS (I may have been one of the last according to some folks I have spoken with!). I also found its claim of carefully handling conflicts accurate. Like rsync – it of course can work over enrypted connections using ssh.