I like the idea behind Gutenberg and can see the long term advantages.
However I still have real concerns at the speed this is being introduced and even Joost de Valk has published this report https://yoast.com/gutenberg-alternative-approach/.

I would just like them to slow down a bit and stop rushing it, under the original time line we would already have Gutenberg and a lot of unhappy clients.
I recommend everyone puts there or some clients sites on a test bed, install Gutenberg Plugin, activate it and then go to those pages you spent hours getting right and after you pick yourself up off the floor right some feedback.
I have a screen shot of what happened to one clients pages and it scared the heck out of me, it's an unreadable mess that will take hours to fix.
Please just slow down and take a breath.