I have navbox lite and find it quite acceptable for my use. Its quick and easy to use and understand and it is not a replacement for drawing lines on charts but it does all the calculations for you and presents them in a user friendly format for use in the plane. The ability to create a waypoint anywhere with its corresponding lat and long - put it straight into the GPS (back up nav of course!) I think pro is supposed to be excellent but much more than I require as a PPL IMC NIGHT rated pilot.