DO NOT DEPEND ON PHONE BASED GPS service. It is lacking at best. I travel rural MO a lot visiting clients. You can not beat a Garmin Nuvi with lifetime updates. I have seen family and friends get lost trying to use the phone based crap. We still have the Galaxy S2 and love them, haven't had a need to upgrade yet. We use ATT, but just because we're already there. Verizon will be a good service as well. Keep in mind, you will not be helped with a GPS in counties that still do not have 911 service like Bates County.
The best way to get to where you want to be in the future is to act like you are there TODAY.