I forgot how long my the process on my PC, but I think around 30mins (probably a bit less than that) on my old-ish ssd. The problem is that my memory kinda mixed up on how long the actual install process took. Basically I checked for update, it downloaded the update, preparing for installation, installing, reboot several times for the actual installation. I assume when someone is asking about how long, they only wanted to know how long before they can use the PC again which is the time I mentioned above.
As for some setting got reset, at least my network and internet setting (the one where you can choose to enable file and print sharing, etc) was back to default. Also my audio switcher app need to be configured again. And I don't know whether this is because of how FCU handles notification or because my customization is removed but when an app put notification and it put up another notification, it piles up. For example, I've got failed upload notification from Google photos upload which before the update it only showed 1 notification even if it reminded me multiple times. Now it keeps every notification from it.