Another update on this one from me…
It’s just over a week since I switched from using Dropbox to Onedrive, and after some initial issues, OD is now working almost as well, in terms of speed, as DB. Something i changed which I do beleive improved things was to set my MBA to download all files, not work in offline mode, or whatever OD calls it. Up to this point OD was really slow on all devices, but once I gave in trying to manage the limited space on my MBA (my only non-desktop machine since the demise of my trusty 17in 2010 MBP) things on all devices has improved.
I did stick with DB for the RW Addons folder, mostly because OD has issues with several Stacks4Stacks stacks, but in the end I’ve just had to drop those stacks and move the addons folder to OD, and thus far, it’s working fine.
In case anyone cares, the issues with S4S stacks is covered here: S$S Spacer & Toggle issue on One Drive