I have found that the Good Sam Trip Planner is not very useful. The Trip Planner wants to load adds while I'm scrolling the map and it places too many options along the route.
I like me Garmin Nuvi 770 a lot! I can add a place, address or intersection and it will direct and adjust to my various decisions. I will utilize my phones Google Maps app to confirm and seek (look for restaurants or attractions) while the Garmin controls routing.
I find that all GPS units are used best for the first and last mile of any trip. The middle stuff is the easy part. Then of course, there is the decision factor.....choices choices!
Sometimes the best option is to just follow my nose! It hasn't led me too far astray......yet! And ya never know, you might stumble upon something wonderful!