I agree with Mockturtle. We've found that the human brain is still the best decision maker! Its wonderful to have the device able to warn you of upcoming lane changes and route changes and such. The long route planning is excellent too. Our experience is that we need to review the route carefully as our RV Garmin has tried to send us on some pretty weird goose chases numerous times. Things like getting off the main highway that's a regular truck route and taking a detour around for about 5 miles on a safe route but a two lane hilly excursion. And yes we have traffic on but there was no traffic. We had it take us on a turn around when we missed a exit that took us back under the highway in an area that we really should not have been (crime) and where we had nothing to spare on height. It also has taken us into the city in areas where turns and traffic were a nightmare. There was even a non existent road in Texas once. Note that this is set at quickest route also. I understand the limitations of map makers but just make sure you are the final decision maker after reviewing!
I don't understand why Garmin doesn't make it like Google where it's easy for users to post updates for corrections!