After my old phone made using my Google Maps impossible, I had to resort to using the factory NAV for once. And my God, it was so crappy I finally bit the bullet and bought a brand new phone so I would NEVER have to use the factory NAV again.
That stupid NAV sent me through the center of the Earth to find a location that was well known and should have been a piece of cake. I checked the system, it was set to fastest route, so no freaking excuse.
Every time I use the factory NAV, I always wonder why did it go that way. Every time I use Google Maps, I think wow, that was a better route than I expected. Besides the garbage routing, you better know the correct spelling or address you are looking for, or it won't find it. With Google, I can just say WalMart on Broadway and boom, it's got it.
I don't mean to go off on a anti-OEM NAV tangent, but I can't tell you how much I don't like using it. The only positive that came from it, was that it comes with a black gloss bezel on the 8.4" screen, which makes it look bigger than it is. It's almost worth the cost in that regards.
I guess in the unlikely event I don't have cell phone connection, it could come in handy.