Aye, no automatic update for me either. I'm about 17hrs in and so far so good. It installed really quite quickly - faster than some of the Marshmallow updates.
Took me 2hrs to find where the WiFi Calling option had been hidden. I've also got an issue with my Gmail app. It no longer seems to be automatically collecting mail. All morning not a single chime from it. Manually opened Gmail and both my Gmail address and personal IMAP account started showing new mail.
Not sure how to fix that one - may see if I can remove the app and reinstall. May also try the MS Outlook app instead.
Both little things. Phone feels snappier, but willing to accept that it might just be a placebo.