I was reading that xUbuntu MATE 20.04 uses less resources on a Pi 3B. I have Ubuntu MATE 20.04 installed and I am backing up everything with Deja Dup.
Is it worth it to switch to xUbuntu?
Yes and no. It kind of depends how much stuff you have installed and running on the system.
(By the way, it's Xubuntu, not xUbuntu MATE.)
That said, sure -- stock Xubuntu with nothing installed in addition to the default software picks will beat stock Ubuntu MATE any day in a fair competition. I probably wasn't supposed to say that, but let's face it -- until XFCE goes fully "GNOME-Lite" in version 4.16, XFCE is still (somewhat!) lighter weight than MATE. The benchmarks state that repeatedly, year after year.
However, if you cherry-pick the packages installed on your Ubuntu MATE system, I can show you how to beat stock Xubuntu's posterior. And when XFCE 4.16 comes along things are not going to look so good for our hero, XFCE. The difference is about 40 MB of RAM in my experience (on other ARM-based systems). You have to ask yourself if it's worth the trouble.
To add to that, you can uninstall the ubuntu-mate-desktop package on your existing system and install the xubuntu-desktop package in its place, and that more or less converts your system into an Xubuntu system "in a flash". Or what the heck, if you're not sure about switching yet, why not skip the uninstalling of ubuntu-mate-desktop and try out XFCE? For reference, the exact command to install XFCE here is:
sudo apt install xubuntu-desktop
Try it out for a while and see if you like it and if you can see a difference. That's my opinion.
Good luck!
Tried it! Even though XFCE doesn't take as much RAM as MATE does, I
don't like the look and it has some problems.
Went back to mate, and removed the xubuntu desktop.
(Quick question- is Ubuntu MATE just Ubuntu with the MATE desktop?)
The application set is a little bit different. So for example the Ubuntu MATE team might deem it a good idea to include Docky or Chromium in Ubuntu MATE (they might, possibly, eventually), whereas the Xubuntu developers might deem it necessary to include Firefox in the base system and leave out GIMP or something. So they are not quite "just Ubuntu with different desktops", they also include unique apps of their own -- but yeah, most of those apps are just because they fit in with the desktop in question better than the more common alternative. That's my understanding.