The three best GPS apps for truckers are Smart Truck Route Version 2, Copilot, and Sygic Truck Navigation. Each one of these resemble what you would expect from an actual GPS unit, turn by turn directions and automatic updates.
Smart Truck Route Version 2 is the one I have been using for several years along with Google Maps and a good old Rand McNally paper atlas for my backup. With this combination I rarely encounter any problems navigating.