LOOK at this app
OK, yes, you CAN get GMaps, Mapquest, and a few other fairly competent free GPS nav apps.
However, look at what this is offering above and beyond basic and simple "turn now" navigation...
There's a frigging rendering of the street sign, and indicators not just "exit left" but which lane to be in at any point and time to avoid being in exit only lanes, or so that you can know both right lanes will exit so you don;' have to change to the rightmost one.
The route planners are actually customizable beyond "shortest" and "fastest"
Speed limit identification for most roads
Real time traffic (yes some free ones do this, including map quest and Google, but they're not that good)
music controls IN the app (no switching)
integrated weather conditions
portrait and landscape mode (only some do this)
Maps are not only loaded on-the-fly, but also work offline for pre-plotted routes. Free map updates are in fact included, and always up-to-date (no annual updates)
Continues voice prompts in the background even when on a call.
Yes, around my town where i know the major and complex intersections by heart, and simply need to find back roads and the odd store, Google and other free solutions are fine. If I was headed through NY, DC, Hartford, Boston etc? trust me, I've tried (and failed) to use simple turn-only GPS in those cities. Knowing what LANE to be in is a damned important feature if you are not familiar with the city. Getting real time traffic and more, even placing calls from within the app without changing screens, and with continual map updates from the same systems that support the Nuvi? Its a one time $40 investment that is far superior to anything available for less.