If you are in the market for a two way satellite communicator I suggest the Garmin Inreach (Mini) over the SpotX based on first hand experience with both. I had given up on my SpotX and went back to the Spot Gen3 for tracking and basic one way communication (checkin and SOS). My SpotX just was not reliable for 2 way communication. A recent issue in Big Bend necessitated the use of a satellite communicator. While an SOS request would have been justified, it made more sense to relay information to the park for needed assistance. I will be switching over to Garmin Inreach when my Spot subscrition expires in December. Your mileage may vary.
Gravel Grinders
Endurance MTB
Bikepacking
Adventure

I've become a fan of the Zoleo platform for this same thing. Easy to use and has been very reliable in the mountains for me.
Thanks for the reminder. For some reason I didn't think Zoleo was 2 way capable. I have an inquiry with them now.
@Spinistry The two way feature requires a bluetooth connection to a second device for message composition and send. Which is a drawback for some. But I found it to be super simple. And it also gives updated weather forecasts based on your current location which is really nice.
@Ron Wadley The Bluetooth via phone app is pretty standard. That's how the Inreach Mini works. SpotX doesn't require the interface but it is much more user friendly than direct from the device.
@Spinistry I've been a long time Spot user but have never really used it for 2-way comms. Just canned update & SOS messages. The main thing I used it for is bread-crum tracking no matter where I am. It's not unusual to have over a hundred peeps at least looking in on a live race track. Plus, it helps give the fam some peace of mind that if I can crawl to the SOS button there's a chance I'll survive. Every year I compare cost, tho......
brand....device cost....subs cost
spot....125....12
garmin....300....12
zoleo....150....26
BUT BUT BUT if 2-way comms is the prime feature you seek those device/subs costs are probably a little different. Device cost would be higher for spot. Not sure about zoleo. And, of course, if you already have the device....
Unfortunately 2 way on SpotX just isn't reliable enough for whatever reasons. Sometimes I have sent messages (non critical) and didn't get a response. Later I would find out the intended recipients never received the message even though the device indicated that the message had been sent. Spot suggests waiting up to 30 minutes for a message to go out and another 30 to receive a response I think? That's a lot of doubt time. I've been using their traditional trackers for years with checkin message functionality and still highly recommend that for people not looking for two way communication. You can pick up used Spot Gen1-Gen3 for anywhere from $10-$50 almost any day of the week