Hi Eagle,
Personally, I do not trust SPOT’s reliability for getting a safety message out. I use mine to give some comfort that I am still moving (that is if it functions which it does most of time) and “where is Jan?”.
For getting a SOS out, I always carry a GME MT410G 406 MHZ PLB on my belt so if I need to seek urgent assistance, I can get the message out. That is the only reliable international emergency service as it uses the dedicated Cospas-Sarsat international satellite system for search and rescue (SAR) and not a commercial system with limited global coverage (SPOT uses Globalstar – a low Earth orbit (LEO) satellite constellation for satellite phone and low-speed data communications).
As we are very often away from civilization, it gives that little bit of extra piece of mind.
Cheers, TT