Re: "the system has a more modern and 'flatter' look"
For me, i don't consider kde an option ever because it wastes so much resources on eye candy, bogging down my system. In a vm kde is unusable too becsuse it is so bloated.
Then again, I don't use gnome either. First thing I do is install xmonad, a non-decorated tiling window manager. I come to my computer to do stuff, not to get dazzled by eye-candy or getting rsi endlessly arranging windows with a mouse.
Multi-monitor support also sucks for both kde and gnome.