As a UM 20.04 user, I've used this operating system for a while. It works well on the Raspi 3B, and I enjoyed it. Even though they say it kind-of works on the 3B, it works pretty well. Ubuntu MATE on the Raspi 3B works good for smallish things, but I wouldn't recommend hefty browsers (like Chromium or Firefox) especially if you have one gigabyte of RAM (well ~820, since some are given to other resources). I also don't recommend installing different DE's (Desktop Environments) since you might break the MATE desktop.
So recently, I've decided to upgrade to Ubuntu MATE 20.10 to see the new features (and hope to fix some problems). It didn't take as long as upgrading from 18 to 20, but it still took a bit of time.
I've used this for about 48 hours and it seems good. However, some packages I use in 20.04.1 are now obsolete in this version of Ubuntu, which is unfortunate.
There are some minor changes in this release, some like the login screen shut down options. There are three options instead of two, with an added Suspend option. Moving the windows in the DE is a bit wonky. There aren't too many big changes as I hope there would be, but that's okay.
So what do I think about this distribution? Should I have stayed at 20.04.1?
I think it's pretty good, I liked the Fossa better than the Gorilla.
Yes, I think I should have stayed on 20.04.1. 20.10 is not an LTS OS, and I will only have support for about 9 months instead of 3 years.
But anyway, great work for those who were involved in the development of Ubuntu MATE groovy.