Emergency beacon..?

On rando events I seem to find myself riding alone pretty often so am wondering what is a good emergency beacon device? I've looked at the various SPOT devices, garmin, etc but am wondering what the rando community thinks about these? Any comments on the frequency of beacon, battery life, size and weight of device, cost of device, cost of subscription, using Ride with GPS, Strava, or other cell based beacons?

Thanks in advance -
t