Good thing, I have disabled auto updates on most of my client sites, and my own sites, but I just couldn't resist to see what's really new, test it out and also see gutenberg first hand coz I haven't tested the plugin when it was introduced as a plugin before.

Luckily, all plugins I am using on all of my sites and client sites are compatible after I updated one of my site. So, I updated all and asked my clients to test out the new editor.

I currently have 24 clients and 21 want the Classic Editor back so installed the classic editor plugin for them. The other 3 have experienced with drag and drop plugins so they like it.

Regarding speed, I never notice any sluggishness after updating except, for my very own small web hosting business site. Probably there are a couple of custom made plugins not compatible yet. I still havent work on it so I just uploaded my back up to restore it.

Personally, I hate the gutenberg after I saw it, or just maybe I am still not used to it. Only time will tell, but we do need changes from time to time.