It seems to me, after a few years and several different GPS units, that it isn't the GPS system, but one or more of:
The mapping
The settings
The operator
Mapping can be inaccurate, and of course can also be out of date. One route I follow for example, was only opened a couple of years ago, as a freeway bypassing a number of towns. It confuses the hell out of the GPS built into one car, because that GPS mapping dates from 2011, and hasn't been updated since.
The settings seems to be the next one. You can set your typical in-car unit to avoid minor roads, for example, or avoid toll roads or U-turns. I've learned this after a couple of times using GPS in rentals, and discovering that the GPS is set to avoid toll roads and so it sends me through the suburbs.
Finally there's operator error - the obvious issue when people do silly stuff like heading off into the scrub just because "the GPS told me".
I am a fan of GPS, and use it both in-car and in the bush. I find it a really helpful technology - I wouldn't want to go back to the days of pulling over to check the street directory, and I find it great in the bush for marking downed game, marking the position of camp etc. However I don't give myself over to it completely and always have a back-up (map and compass). Only an idiot would give over all the decision making to a device.
