Just a quick feedback to those who recommended SyncBack. The tool is very powerful. I still have some problems distinguishing between Origin/ Destination and where those terms suddenly become right & left (and one has to wonder whether the origin the left or the right was...)
...... but I might be persuaded to buy it
I still personally prefer the User Interface of AllWaySync (cleaner and more graphical, in my opinion), and the fact that it can sync to more than 2 folders at once, but I'll test some more over the week-end.. Thanks to all.
P.S. I am in no way affiliated to AllWaySync.. in case anyone wondered.