The process basically just worked, although it took a bit longer than Apple claimed, and the system was pretty unusable during the post install optimization phase - budget at least a couple of hours, or perhaps a little longer.
A few things needed nudging:
- Dropbox needed a reinstall - just like after the 10.9.5 upgrade
- Amazon Cloud drive broke and needed a java install
- GanntProject (admittedly I was running quite an old version) broke and needed an update