Only problem with it so far is I have a 100% record of leaving it in the glove compartment of the car when I go flying !!!!!
Now I feel bad, since I was the one who recommended Spot 3 to pb84!
RBF,
The nice thing about the Spot 3 is that it talks directly to satellites, so cell tower coverage is not an issue - it works almost everywhere in the world - see this coverage map:
Network / Satellite
Most cross-country glider pilots that I know in Canada and NZ use one, strapped to their chute harness.
I use it when I'm flying and also when I'm doing long car trips, particularly in remote areas.