Xfce 4.14 is the latest stable version of this lightweight desktop environment, and sees all core components ported to GTK3, most gain GObject introspection support, and everything else benefit from refinement and bug fixes.
For instance, the window manager xfwm4
now supports Vsync, works better with HIDPI monitors, and leverages XInput2. It also boasts better integration with proprietary Nvidia drivers, and sports a new default theme.