I do a lot of riding in areas with no cell coverage and very little traffic. I've been using a SPOT for several years. I even pay for the "bread crumb" feature that sends my position every ten minutes. Every so often, the information gets stuck somewhere on the server for an hour or so and then updates all at once. This has caused some consternation for my followers. You can pay to have the SOS button send emergency crews to you, including a helicopter. At least that's what the brochure said way back when I started paying for it. I hope to never find out how that works.

My sister-in-law, who lives in the Tahoe area, recently got one. She had a good friend crash his mountain bike on a solo ride and it took quite a while to locate him. If he would have had a SPOT, his partner would have known both when he went down and where he was to pretty close approximations and he might have had a fuller recovery by saving those six hours of searching time.