I like KDE Plasma because it uses the same old Desktop paradigm that we've all been used to for decades, which GNOME doesn't have. I really hate its default desktop. I feel it's missing too many features.
What I DO love about GNOME is the limited configurations. (Yeah, I know. Super weird coming from a Linux or KDE user.) I find KDE has WAY too many customizations to a fault. GNOME is more focused. I really enjoyed using GNOME 2 and MATE. It was just perfect.
With the proper extensions, GNOME can be a great Desktop. The best example I can think of is Zorin OS. They really did a great job of customizing it into a more standard experience.
But when a desktop environment needs so many extensions to make it (in my opinion) useable, then the environment is a failure. KDE Plasma is ready to go out of the box.
Again, that's my opinion. You don't have to agree with it.