I like that it shades the notifications, and the light mode and dark mode is neat, but the sidebar is horrible, and I miss the background image, it looks bland without it.
It looks horrible, editing is wrong, it looks bland, the side bar sucks, and I'm overall not a big fan. And for someone who has been on FANDOM for over a year, I do not like UCP
Any time the "Related community" thing shows up, it completely disrupts the page layout. Which can be pretty annoying, especially when the community isn't actually related at all - which is the case about 95% of the time.