MobileNavigator [App Store] has a striking on-screen display, with many features lacking in some of the other products that are out there. Unlike the AT&T Navigator and the G-Map apps, MobileNavigator allows you to access your address book for destinations. It works in landscape or portrait mode, and can warn you if you are speeding. It does not have any traffic info, and you can't call any phone numbers that are in the POI (points of interest) data base. A take me home function is done with a single click.
All the maps are loaded on your device (1.29 GB) so going out of range of an AT&T cell site is not a worry. If you get a call, the guidance stops, but resumes automatically when you conclude the call.
Maps can be 3D or 2D, and the 3D maps look great and closely mimic what is on the road in front of you. The voice directions are quite clear, in contrast with the AT&T app, which is garbled and pretty much a waste.
So how is it on the road? Pretty nice. I got a quick GPS lock. If for any reason you lose GPS, in a tunnel for example, you get a red bar across the top of the screen.
You can display POIs along your route, and many of the icons have company logos like Best Buy, most of the gas station logos, even Quiznos.
If you are navigating the next street to turn on is at the bottom of the screen. If you are not navigating, you see the street you are on. At the top of the screen you get the arrival time if you are navigating. Touching that part of the display will give you your speed, and another touch gives you the distance. Many streets alert you to the speed limit, and if you go go over, you can set a warning.
Intersections on highways are handled very well, with nice big road signs and clear directions of where to go. The voice directions come at the opportune times, and do not nag, the way the AT&T app does.
At my location, southern Arizona, the maps were complete and there were far more POIs than provided on the G-Map application.