I'd like to see a comparison to the Mint version.
For the inexperienced, Mint has three 'flavours' (in Ubuntu-speak), vs. Ubuntu's eight. There are Xubuntu, Ubuntu MATE, and Cinnamon (GNOME, the no-equivalent default).
I came from Mint out of tech troubles there, but I was on XFCE and never gave MATE Mint a shot.
Why would anyone choose one version of MATE over the other?
Really Linux Mint MATE isn't that much different from Ubuntu MATE -- the difference is mainly a different panel layout (by default) and some other tweaks here and there around the desktop. Most strikingly, there is a panel off to the left side with launchers much like what Unity used to have, and a panel at the bottom with a searchable applications menu. Basically the Mint MATE version is tweaked a bit to make it look more like a lightweight version of Cinnamon -- Cinnamon is primarily developed by the Mint people themselves, last I checked.
In other words, under the hood they're not very different, and user interface-wise they can be made to look extremely similar to each other. Heck, you can make MATE look a little like XFCE if you wanted to.
Basically you don't choose Mint MATE over Ubuntu MATE due to huge user interface differences -- you do so because there are other applications like software installation tools which are unique to Mint. That's mostly it. But this comes from a guy who used Mint only briefly, about three years ago, before realizing I didn't like it.
Hello jasum
One clear difference is the use of snaps.
[1] https://www.theregister.com/2020/06/02/linux_mint_team_snap/
Snaps are used in Ubuntu-Mate for (a) Ubuntu-Mate Welcome and (b) the software boutique, just to mention two main items.
There are other differences too, that the mint team make to the Ubuntu base that they use, but that gets more technical than most people care for.
Summary
They are similar, but not at all the same thing.