All of the composited Linux desktops are also rather sluggish. I still have not heard a compelling explanation, why this is. Even a simple window minimize zoom animation gets choppy on low-end hardware. Get an Atom netbook and compare MATE/Cinnamon/GNOME/KDE/Unity (so basically any composited desktop with animations) with Windows, and the experience is worlds apart. There is something wrong with the graphics stack (compositor, X.org, kernel drivers?) which no one wants to admit. However, at the same time, a single OpenGL context (such as a game) usually runs at great performance under Linux.