As a long time Mac user I find KDE hard to enjoy. The UIs of KDE apps are almost universally overpacked, messy, or lopsided (one side of the window had its controls crammed while the other has awkward white space). It might sound like a silly gripe but it really bothers me. The design of apps from GTK+ desktop environments (GNOME, Cinnamon, Pantheon) generally feel much better, but they have their own problems.