I test drove a truck with the built in navigation and it was nice. It actually showed the current weather status (rain, snow, sunny, etc) in the clouds above the vehicle. But for the price tag of that truck to mine, Google maps works fine.
As for a GPS mount, I can't use it anymore cause my phone is too heavy but I use to use the one you would see on TV with the sticky green pad. Actually works great for a smaller phone. Now that I have a note 3 with a massive extended battery it damn near rips the thing off the window haha
Sent while in 'Murica...