I use this device and app in yellowstone and it has performed flawlessly for two years now. Why do idiots go hiking without a device and service like this?
I also love the fact that the device can be used with other third party apps like MotionX GPS. I still turn on track datapoints every 15-30 mins. I keep a back up battery for my iPad and extra AA lithium batteries in my pack at all times. A NeverLost for your person.
Sterbenz about Earthmate