I use the Tom Tom app on my iPhone and very happy with it both in NZ and two trips to the USA where covered the West Coast in 2012 (LA, Vegas, Yosemite, SanFran, San Diego, LA) and last year (New Orleans, Orlando, Savannah, Washington, New York) Next year we're doing Yellowstone, Oshkosh, Chicago, St Louis, Nashville, Indianapolis, Chicago and will use the Tom Tom App again.
The only thing that caught us was accepting an update, then finding out that hotel, mecca's, cafe WIFI's wouldn't let us complete the 50meg download so for a few days we had to use Google Maps which cost a bomb in roaming charges. Now we buy a USA sim.
