The only time I realised that his GPS navigation is turned on was when he went through the tunnel. All other times the screen was practically unreadable in broad daylight. I have an R1200C and I contemplated installing a navigation unit. But it seems to me that it's nearly impossible to use it during day time :(
Maybe it's the angle of the camera that makes it impossible to see the screen in the video. I could see it while driving my C. The navigation system was a Zumo 660, meanwhile I have the BMW navigator 6 and it's screen is much better (but anyway also the Zumo 660 worked in the C).