I work in the GPS navigation industry. I recently tested the Garmin nuvi 770 and it was very easy and intuitive. All in all, Garmin makes very good products and if I were to purchase a device, Garmin would be the company.
Yes, it is true that you can use your phone for navigation. A couple of pointers on that, though.
- The map is not resident on the device, so you will always need a wireless connection to use the service. This applies equally to iPhone nav and VZ navigator and the like.
- What happens if you travel overseas? If you are on Verizon, you are SOL and will need to use maps or rent a device. If on AT&T then get ready for the huge data charges for roaming, plus the license fee for another map region.
- What happens if you have no cell coverage? Simple - no navigation service.
- You do not own a perpetual map license with a subscription model. End your cell service and you lose the map. Plus, 18 months of $10 per month and you have paid for a dedicated device.
- Screen coverage and memory: You cannot add POI data sets to your VZ Navigator. So if you want to download a a scenic route tour you are SOL.