Response times vary all over the map, depending on weather, distance to be covered (driving as well as hiking), familiarity with the terrain, and a host of other variables. I would suspect that many people carrying a PLB expect that if they trigger it, help will be just around the corner. While a PLB does generally shorten response time, it doesn't always turn out that way.
On the other hand,I will always remember a climbing trip i did with a good SAR colleague,, who invited a friend. Hiking up the trail, we countered a serious accident(obvious head injury plus??). Then I learned that our third guy was an ER physician. My buddy had brought along his SAR radio, not leaving it in our vehicle, which was parked in a deep valley. He immediately made contact, a long shot because the frequency was not monitored when no rescue was active. Another rescuer returning from yet another ops got his transmission as he was pulling into his driveway, and within an hour a helicopter was hovering overhead, ready to hoist our victim and whisk him to a hospital - two hours elapsed time from accident to the ER. This situation could have easily taken a day or more to resolve.
Even at that, two hours to the ER is not great with head trauma...
I never tire of telling this story, which I call the "Perfect Rescue." Did I mention that our dates were impressed??
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Geezer in Chief