Just a report on this (file synchronization).
I've installed syncthing on the three systems where I want to synchronize files and, so far, it seems to be doing what I need.
It has a nice simple easy to understand web GUI.
It doesn't "automate" very well, it's designed more for a single user sort of scenario. There's no ready-to-go set-up for running it as a server and the documentation says add it to the GUI "run at startup" settings but this of course means it will only run when you actually log in to your working desktop. If the system gets rebooted remotely for any reason you won't have syncthing running.
I have thus added it to /etc/rc.local, however even this isn't particularly tidy as it needs to run as the user (not root) so you have to do:-
su -c '/usr/bin/syncthing -no-browser -home="/home/chris/.config/syncthing" -logfile="/home/chris/tmp/syncthing.log"' chris &
It's also almost impossible to run without the GUI, so to manage the remote syncthing on my web server I *have* to allow external access to it.
However, as I said, it does seem to do a good job of synchronizing files across my three systems.