The only real diff is you have to use the desktop's display resolution and bit depth, whereas real fullscreen lets you choose the display mode.
Also currently on the Mac there is a bug when opening a window without WINDOW_TITLEBAR, which causes a crash. Also on the Mac you can't open a window that covers up the title bar at the top of the screen.
Also currently on the Mac there is a bug when opening a window without WINDOW_TITLEBAR, which causes a crash. Also on the Mac you can't open a window that covers up the title bar at the top of the screen.