My experience with the Spot X - was checking in every night from the same location, and open area, good sight of the horizon in all directions.
Made connections and subsequent texts for a few nights in a row, no issues. Then the 4th night I got no bars for satellites and it was perpetually searching for a connection. did all the troubleshooting steps, even moved to a different location, nothing. I left it for several hours, no connection. I did not gain a connection until almost 24 hrs later.
I'm assuming, with common sense, that a connection is necessary to make an SOS.
I was in a 'remote' location, but not as the crow flies in terms of being surrounded by cities, etc.
Had I would have been in distress and needed an extraction, I would not have been able to rely on the Spot X in that situation. I realize nothing is perfect, but after that I lost all confidence in the product and would rather try a different one to see if I get the same or better reliability, worth a shot, when your life is potentially in danger.
I also realize that yes, 5 years ago or whatever, this type of device was not readily available, and people had to deal with it. I'm making a statement on the product and not whining that I was unconnected.
Also, this is only a few weeks ago, I cancelled my annual Spot service, but was lucky as it was on the date of renewal. No heads up e-mail message or anything. I though that was shady and not in the best interest of the customer. They also make you call to cancel your subscription so they can hound you to try a different package etc. Joke was on them cause i changed my CC, but still, it's the principle of it all.