I bought a SPOT Messenger before the November Coues deer season here in Arizona. Was planning to hunt solo, and wanted the peace of mind of being able to signal both my state of well-being (on a regular basis) and the need for emergent or nonemergent help (should the need arise) to family and friends for those places out of cell phone range. As luck would have it, I filled my tag on the first day, so didn't have opportunity to give the device a fair test. To date, though, I've used it (using the "OK" button) to signal my starting point/vehicle location for coyote calling and squirrel hunting here in northern Arizona. As long as there's open sky to establish a GPS fix and send out a satellite phone signal, it seems to work as advertised. A coworker used his last month to call in National Park Service rangers for a fellow hiker with an open tib-fib fracture from 600 feet below the South Rim of the Grand Canyon. The company is selling the units at present for $150 (with a $50 rebate), and annual connect fees of $100 for the basic service, which is all I felt the need for. My wife takes this unit with her, as well, when she rides horseback into the mountains.