Down in Donner SP playing with the new toy - Apple started approving external gps hardware for the itoys, and there are three of them out already, so I got the bluetooth one (the other two are attached by cable and directly to the bottom, both of which seem unwieldy) to see how they work and if it would magically give it perfect gps accuracy.
So mine is the
Dual XGPS150, which is pretty small and light and red. The bluetooth bits were fine, it worked right away, but the gps accuracy was a bit of a disappointment.
Screenshot of the Dual vs the built-in ipad gps. The Dual was the lines with grey dots, the ipad gps was the ones with black dots. I was just walking circles around the roads, which were mapped easily from the aerials, which were aligned by wms, so they're definitely in the right spot. I had the bluetooth part on the arm strap that came with it (worst velcro ever) which I figured was the best spot for it, but then while walking back to the car I took it off and wrapped it around the top of the ipad, and that actually seemed to improve it, but I didn't feel like walking back for another lap around the roads. So maybe I just need a JJ hat.
So survey says: inconclusive. Though if I had to give an intermediate score, I'd say Apple: 1, Dual: 0