I wonder how using your phone for GPS would work in areas/states where there are no texting laws? I have both and use both, I prefer the GPS for the screen size and ease of use. I use my phone in my work truck and it is a pain to try and take a quick glance at the screen to see where the next turn is.
I have a Garmin smart link on my phone that I can enter routes or destinations into and when I get in my personal truck it will sync with the GPS and everything will be there. It's great for route planning and takes the hassle out of entering everything by hand in the truck.