We have been all over the US & Canada some pre-RV and a lot with our RV. Evolved from Rand McNally maps, DeLorme software on a laptop, GPS, and increasingly with my smart phone. Still carry a Rand McNally atlas, but seldom reference it.
As many have said, common sense is the key. Yes, our GPS (4th generation) occasionally does a dumb route, but the aid of the GPS far outweighs this downside. Also, GPS searching for a destination is not up to par with Google Maps on a smart phone and can be maddening at times. But again, the GPS wins out due to its many benefits. To match a GPS with paper maps, it would be necessary to not only carry a road atlas, but also county/province maps of every county/province in North America.
Those that bad mouth GPS's must not understand how to use them without committing blunders and/or what features they have.
And there has not been much mention of the GPS's main feature. It is impossible to ever get totally lost with a GPS. It always knows where you are even if you don't. Just put in a known destination and it will get you from where you are to where you want to be.
I do think GPS's will lose out soon to smart phones/tablets due to their better user interface for generating a route and their searching capability. I often find my Garmin GPS cannot find a destination due to my not matching exactly how it knows that destination, when my Android smart phone instantly finds it. Only a few obstacles remain like the need to be Internet connected and the while driving interface that is still inferior I think to the GPS.