Just briefly, the navigation screen gives you true "touch screen" control of your audio, climate control, navigation, points of intrest such as nearest Chinese, Italian, etc. resturaunt. as well as voice command to change channels, raise/lower temp. and about a 2 inch thick owners manual that comes with it.
Paul
What I'm trying to say is, it does a great deal. That is why you need the thick manual. It is fully integrated with the ES systems whereas my Garmin is not. Both navigate well. The Lexus nav just does more. Did I mention the back-up camera on screen.
Paul