Kubuntu 18.04 LTS looks good. Pretty mainstream, recommended by Juan Conejero.
"Kubuntu (/kʊˈbʊntuː/ kuu-BUUN-too) is an official flavour of the Ubuntu operating system which uses the KDE Plasma Desktop instead of the GNOME desktop environment. As part of the Ubuntu project, Kubuntu uses the same underlying systems. Every package in Kubuntu shares the same repositories as Ubuntu, and it is released regularly on the same schedule as Ubuntu."
I doubt I'll switch, but perhaps. I may try installing KDE on Ubuntu, I think that's where the name Kubuntu originates.
Another possibility is to install KDE on Linux Mint. But I see no real reason it would be superior.
Edited by bobzeq25, 19 September 2019 - 04:21 PM.