GNOME. However, I use ArcMenu and Dash to Panel to get a KDE/Windows style taskbar UX.

Why do I use GNOME then, you might ask? Well, I really like the simplicity and aesthetic of GTK/Adwaita. KDE is too noisy - for example, the built in text editor (Kate) can double as an IDE, when all I'm really looking for is a box I can type in.