Not sure what light there is to shed. I installed Ubuntu Mate on a Pi 3B following whatever instructions there were and I recall it worked okay and as expected as far as I used it. Then I decided Raspbian was better for me and went back to that.
Get a second SD Card, install Ubuntu Mate on that, boot it up, see if you like it. If you do; great. If not it's a simple swap of cards back to what you currently have.
One big positive of the Pi using SD Cards is it makes it unbelievably easy to try something and back out of that.