The most important challenge these GPS units had to face was my ignorance. How hard would it be for a techno-illiterate like myself to take a GPS straight out of the box and-without referring to a manual-gain satellite reception, mark waypoints as I zigzagged the half mile downtown, then turn around and backtrack my route home? All four units passed this initial test. I then hiked in the mountainns to test reception and various navigational functions. Water-resistant models were submerged in a bathtub for half an hour. Finally, I called the technological support numbers and, without identifying myself as a Field & Stream contributor, asked company representatives dumb questions. The advice I got from all three reps, who walked me through various navigational forests while I pondered and poked at control buttons, is proof that patience is not yet one of this century's lost virtues. -K.M.