Originally Posted by
kch50428 But - having the stand-alone device, and a decent nav app gives you the best of both worlds - the stand-alone device can 'stay in the car' for use while on the road... and the app on the phone for times when you're not in the car

And this is good how?
Use a tomtom mount and you've got a GPS (navigon), music player, a place to put the iphone, and its being charged. It's simple grab and go..snaps right in...or out. When not in car, no worries about a gps unit being stolen..its in your pocket.