As someone who hosts over 150 WordPress websites for small businesses ... I'm not thrilled about this release and the work it will entail given the editor overhaul.
The drop in boxes on 5 were too small on my system to edit (looked like it had a max width of 600px. This essentially forced my hand for the classic-editor because I couldn't drop in images and what not. Really strange error to have on the first day.
The boxes for editing should be based on percent (I shouldn't have to edit them).
I manage a fair amount of WordPress sites. You need to add all your websites to a WordPress manager like ManageWP. Install the classic editor. That will give you time. We will not use Gutenberg for now. I'm creating a training to help everybody use it.
I just tried updating to 5 on a test copy, as far as I can tell it didn't break anything.