How good is the 09 MMI (Nav) System?
 

I just helped my dad spec out and order his new '09 A4. He got the Tech Package and ADS. I told him that it's easier and cheaper to have satNav in other things (like our phones, external GPS modules, etc). But after looking at the full MMI system, I really 'want' that central knob with all the buttons. I'm a big gadget nerd, so all the direct access with the buttons and better customization through the full MMI really gets to me.

But ultimately this is not my car (although maybe I get to drive it some). Would it be silly to push him for the Nav system?