I don't use them because I have been around here, but I have been told by everyone I've met visiting this area they are great. Well worth the extra money you spent to get it in the car.
We travel a lot; and the GPS has been a god send. I don't even look at maps anymore just plug it in and listen to what "Lori" tells me. Which sometimes is " at the next opportunity, make a U-turn"
Don't use it at WDW cause we're their frequently; but for central Florida; Toronto; West coast; Idaho; Wyoming, etc. it's worked great. And makes it easy to return to airports; which has been a bugaboo from time to time.