We have our SatNav (TomTom 710) on the dash in the middle (ie between driver and passenger). The centre position on the dash is great - we can both listen to the spoken instructions and see the display, the driver only occasionally glancing at the screen in the same way that one checks the rear-view mirror.
The holder is permanently installed in place of one of the air vents, and so looks inconspicuous when the SatNav is undocked. When leaving the car we undock the SatNav and take it with us.
jiva (Jimmy & Val)