On Android it's freaking fantastic. Everything feels snappier and I can utilise uBlock Origin to block all of the BS. I've set this up for family, friends etc and none have gone back to Chrome. I think the biggest issue is marketing.
The total rewrite might have given some performance boost and if that's worth it for you then I'm glad for you, but unfortunately it also caused loads of bugs and features that have gone missing, and now that the big push for the rewrite is over, tackling those remaining bug fixes and missing features is again happening at a rather glacial rate.
And the frustrating thing is that this used to be a problem even with the previous iteration of Firefox on Android, i.e. it seemed somewhat understaffed and had some surprising bugs (e.g. under memory pressure it would suddenly and silently stop remembering your current tabs) and missing functionality (it didn't remember your scroll position if the app was killed, you couldn't reorder tabs in the tab list) that were only fixed after years, and even then quite a few times only through outside contributions.
And now the rewrite means that all of this has been thrown away and judging from the current development speed it'll take once more years until we sort of get back to where we used to be.
Also, Firefox 79+ on Android (August 2020) performs significantly better than older versions, despite having lost many features in the rewrite. The current version might meet your expectations.
Yes. They did a rewrite of the android UI layer that released last year, and since then the scrolling is on par with chrome. If you install ublock origin then Firefox now has the best android browser experience by some way.
