Never, never, never rely solely on a GPS. Always have a paper backup. I have owned several and have learned to only use it to get me to the next fuel stop, after confirming the route. If you only travel major highways and interstates you may never have a problem. But the wife and I prefer the two lanes and small towns. It takes planing and knowing your route to prevent being sent down a dirt road, or worse yet no road at all. As happened to us.
Thanks for the info on the 760. I'm still debating as to the need for one.