My three w10 machines have gone through the 'update' over the past few days. As far as I can see, they've all survived, and seem to be usable in much the same way as before. Of course I'm not necessarily aware of or using many of the 'features' of W10. I use Classic Shell as the main operating interface, and I persisted with setting up these installations as networked machines in my existing W7 (and up until recently XP) devices, so the disappearance of the Homegroup facility goes un-noticed.
I brought a new Dell i7 Win 10 desktop machine into the system about a week ago and setting up permissions for disk and folder access for this one seem much more complicated than previously. However I fumbled and blundered through the process with frequent calls upon Google, and it seems to be OK. It's nice and fast, which is what I was hoping for.
I'm almost sorry that I denied my W7 machines the offer to 'upgrade' to W10 when it was free, but having heard the tales of woe from friends who did so - only to find that printers and other peripherals were no longer usable - well, perhaps I made the right decision.
Regards
FOR