K.S.
I do not know which one is best, but I will tell you that they get their maps from mapquest and google and arent very accurate either. Maybe some of the more expensive gps's might be better. YOu will definately have to download the latest maps to be accurate. And preview your trip on your gps before taking it.
I have a Magellan, about $120 and have used it once for a trip to SC and to find my way around down there. It was useful but it took me AROUND my destination several times instead of using a direct route. Good thing I had printed directions offline to go by or we would have gotten lost.
Good luck.