I have used my smartphone as a GPS in the woods and it worked well. There was no cell service so we downloaded all the information for the caches we planned to hit ahead of time. Once I was out of cell range, I put it in airplane mode to stop searching for service. I only used the GPS with the preloaded cache information and the phone lasted about 6 hours. I think it works well but I would be curious to try a handheld to see if the accuracy is really that much better. $400 is a lot to spend on a unit that will only get me another foot closer to the cache.