I'm using both a CAA TripTik and a GPS to navigate me on my trip.
The GPS and I have an uneasy relationship. In the Ottawa tryouts, I would leave it chattering happily to itself on the dash while I ignored it and went about my usual routes. I noticed it had a malicious streak, and more than once tried to turn me down a torn-up street, that I never previously even knew existed, on a cross-town trip.
I like having it on the long trip. In order to keep conflict to a minimum, I don't tell it we're going all the way to California, I just give it that day's hotel destination, and we usually more or less agree on a route (especially when the route is generally "take ramp to I-70, drive 6 hours, exit on the right and turn left..."). I already know where we're going (we being the GPS and me) by the CAA Triptik, so the GPS is a reassuring back-up.
The GPS does not like stops for gas or burgers, however, and nips at my heels like a sheepdog at any deviation from the road. I find too that if I miss an on-ramp, (always intentionally, on my way to feed self or car), it will try to send me down the on-ramp in the opposite direction, as if we might as well just head home if I won't listen to it. It will also sometimes sulk once I return to the car, and not talk to me, but will still grudgingly give an approving chime when I turn back onto the highway.
In Kansas City the GPS got the better of me. On my CAA TripTik, it was kind of missing a small segment at the far side of the city, so I knew I might have to look for a ramp to stay on I-70. So, when the GPS urgently told me to take an exit, I believed it, although I also missed the exit, as it did not say I-70 as I would have expected.
The GPS then demanded I take the next exit, which I did, only because I had no time to think. It then turned me around and sent me back east, and then onto a highway headed south.
I was getting pretty nervous at this- south to Wichita, Kansas was not on my route! However, I decided to trust it and take it's route, especially since I was getting lost at this point.
Around 10-15 minutes later, it turned me onto another road heading west, which I was relieved to see was marked on my TripTik, and which merged with the I-70 ahead. Unfortunately, traffic was building at this point (my original plan would have had me clearing the city just before rush hour).
The road turned into city streets, and then the GPS turned me north, and then east again! I could see the highway south of me, so I figured we were taking a typically unconventional GPS route back to it.
Then... it turned me north on a dirt road! A DIRT ROAD! I was supposed to be on the interstate! At this point, I was lost, so I gritted my teeth and decided to trust it, because I had no time-efficient alternatives, and besides, we were only 150 km from destination...
Another dirt road later and we were back on a regional road, which morphed to country road, then to 4-lane divided highway (but not the interstate), and back and forth. Eventually, we got back on the highway. Later, I figured out it had been configured to avoid toll roads, and I guess I-70 had a small toll section on it. It did take me back to the I-70 eventually, and then on to destination.
It was nerve-wracking, but also reassuring that it did get me to destination, although probably an hour and maybe 50 extra km's later.