I jumped at the opportunity and upgraded to Office 2016 on my Office 365 subscription, and to my surprise, the upgrade process itself took almost 2 hours to complete. If I'd known, I would have waited until later to do so. It took me just 20 min to install brand new Office 365 (2013), so there is no reason why Office 365 2016 would take 4 times as long.
Now all of the Office programs are running slow, often with (not responding) msg before returning with the information. What's up with that? This is the public release and NOT a preview version, right?