I've been disappointed by the built in Nav systems in my daughter's last three luxury cars. While easy for her to use, data updates are expensive and the data sparse outside major metro areas. Usually no county roads, no streets in "small" cities except for route through town of major highways.
Went through Atchison once, wanted to stop at Amelia Earhart birthplace. Sorry, no street or POI for Atchison, KS, a county seat and transportation nexus with population 11,000. I had found it the year before with my Garmin, so had I good idea in my head of how toget there.
Routing algorithms were also an issue. The Honda Nav wanted to use 6 mikes of expressway to get to a place three miles away on surface streets, in Wichita Falls. At least there the streets were in the database.
