The problems with the globalstar constellation are well documented if you look around.
Personally I would go either for an epirb with a 406link.com subscription where the self test function allows you send a position report
Or: just buy an Inmarsat iSat phone pro sat phone. They are bloody good sat phones and not expensive to buy. Plus you can text or email a position report and the phone calls are pretty cheap on them these days.
IMHO if I was in the shit in the middle of nowhere I’d like to be able to speak to someone as well as just sending a message. I do have to hold my hands up though in that I do work in sat comms but I have had a few clients that have given me their feedback on the spot system. At the end of the day, you get what you pay for and for £100 the spot is a good peace of mind solution for slightly remote locations however if you are working in a hazardous remote location then I would expect my employers to supply more than just that.