Since this appears to be a very smooth update for me and for most people, I'll take this opportunity to provide a little feedback on the rough edges.
Last several updates, it's been necessary to update-grub manually in order to get my other multiboot partitions back on the grub menu. It always works, after that extra step, so no harm done. Just an extra step.
The other thing that happens often, over an even longer period with Manjaro, is that certain applications won't work after updating, and need to be reinstalled ... even if they weren't updated themselves specifically.
Filezilla is one this happens a lot with, but not this time.
Freefilesync broke this time. There were notes for it in the AUR ("uncomment line 34"), and after following them it reinstalled correctly.
Currently the only semi-permanent casualty appears to be Iceweasel, which isn't finding a source repo at the old URL. Upstream issue no doubt.
These applications that break often on update also seem to have one other interesting thing in common. If you go in to Add/Remove Software and search for them, they end up being listed as in the Manjaro repos, as well as available from the AUR. Best I can tell, the showing up in the repos part is a bug--they're not really in the repos, but AUR packages pure and simple.
Anyway. That's my fine-grained complaining for the day. Overall I continue to be quite happy with my OS and grateful to you all for the work you do.