[Fat Charlie]

My issue with GPS isn't how much accuracy the system is capable of when locating a particular point, my issues are with how much varying accuracy and refresh rates are combined with map databases, churned around in a computer program and spat out as route information.

I've watched the number of satellites that my system was tracking fluctuate and the quality of grid it was able to give me fluctuate along with it. You can lay a slick UI on top of that to give pretty pictures and reports, but that UI is making a lot of assumptions. I'm going to use Torque and My Tracks to see how close they are, but I lean towards trusting a rev counter and OE tire size. At least I know for a fact that they account for elevation changes.