I too, have the Magellan GPS Companion/Handspring combination. Seems to be VERY accurate. Problem is, the Handspring has a mind of its own and requires a reboot ....and I have to reload the GPS software. Not the kind of thing you like in the middle of a hunt. Tried everything, but cannot trust the little sucker. Also have an eXplorist 210, which I love, and is my main unit.