I'm using KDE Plasma on Arch presently but I really do not enjoy it. It's a very ugly, cluttered, and claustrophobic user interface. GNOME is better looking and less cluttered but also feels castrated without installing extensions that break with every update. 

I have high hopes for Cosmic but it's still quite buggy unfortunately. I think they are on a good path but will take time to mature it. 

So for now, not sure what I want to do. Maybe I go back to GNOME and deal with the extension issue. At least it looks and feels like home.