I just bought the EX myself. It hasn't arrived yet, but my understanding is the eggs sit on a round tray with egg shaped holes cut out. The tray spins in a circle, gently turning them on their sides as it rotates.
I have 6 eggs in my new one right now. Every hour you hear a little buzzer as the tray turns slightly and turns the eggs very gently to another position. The eggs lay flat, not vertical like my other incubator.