We took all five devices/apps and tested them side-by-side for over 200 hours. We tested the beacons while boating around tiny cays in the Bahamas, paragliding in Argentina, skiing in Chamonix, climbing in Peru, coordinating charter aircraft in Alaska, and traveling through the jungles of Costa Rica.
We submerged them in fresh and salt water and let them chill out in temps of down to -5C. We tested the Garmin inReach, SPOT, and GoTenna extensively with iPhones. With help from friends, we attempted to pair the SPOT with smartphones running Android as well. We also took these on a 150-mile bike ride on the Kokopelli Trail in CO/UT and on many dirt bike rides and backpacking trips in and around the Sierra.
To confirm signal coverage and message transmission we sent and received non-emergency messages as prescribed and did copious amounts of research. With devices that do not have non-emergency messaging capability we employed the built-in test mode and secured the most reliable confirmation that the device and network allows.