You NEVER rely exclusively on technology for navigation, you have to be familiar with your routes and areas and stay oriented. I ALWAYS carry a hard copy map and maintain knowledge of my locations as I move. The technology can help in many ways, but it is an aid only. All that being said, I found the cell phone signal to be within about 150 feet of where I knew I was, while the GPS jumped around or lost signal. When trying to find a particular business or marking a waypoint, the technology is more helpful, and this was mostly impossible with the GPS.

On a side note, I would like to find the best iphone app which gives the functionality of a GPS (marking waypoints, distance to travel, navigating to a location). Any ideas out there let me know. Thanks.