I suppose the wisest choice of emergency communications mode is to know what is likely to work where you are going.
In my sailboats/kayaks, I'll carry both a marine radio and a cell phone. Sometimes 911 won't work on the water.
Sat phones, hopefully, will become more affordable...they have come way down.
One thing that has never failed me but has been used as only a hobby in the boonies is HF ham radio. I've always been able to make contact but the equipment is not necessarily light weight (2 lbs.), license required (except in an emergency), and some skills are needed. The signal goes around the world if conditions are right.

I do carry a cell phone now, even when coverage is not expected...sometimes...because of stored maps. My old gps lays in the drawer back home. Whistle, map and compass, always.

A friend who hikes the same desert I do, but always solo, puts me on his SPOT email receive list. I find that very useful. I get reports of his whereabouts several times a day. Even if he hasn't changed the message from "OK", but sits in one place very long, I'll know something's up and can call the ranger station. It's been 100% reliable the last three years.