Hands down, our family found this app a perfect companion as we drove the road to Hana, and took some of the other "tours" they suggested.
Hint: Download the tours to your phone because in many places, going to Hana or on the backside loop, you will have no or spotty service.
This is GPS activated telling you where and when to stop, or just as importantly what to skip as you drive around Maui. "Shaka" blends history and interesting facts as he gets you ready to visit some of the great sights. You don't have to worry about looking at a book or what's the "best" sightseeing venue, he just tells you. Some of the jokes are lame, but the Hawaiian music and history "three dimensionalized" our visit to Maui.
One other advantage of having this App, "Shaka" makes most of the decisions, so there is not much arguing or decision making that family has to make, adding to a lot more relaxing and laid back touring around the island
For $20, it's the best Hamilton you will spend. Do it from home and you can even "pre listen" to some of the tours.