For me the biggest thing was cost and pricing structure of the talk time. Irridium is nice but overkill for my use and expensive. If I was traveling the globe and spent much time outside normal coverage areas it might make sense.

Altell sells prepaid phones for about $20 for the basic phone and messaging. For $45 you can get one with a camera and other unnecessary features. The time is structured so that if you buy in $100 blocks you get most of 700 minutes and the minutes don't expire for a year. Which makes it cheaper than a land-line.

At $20 for the unit if it gets destroyed your no out much. And at that rice you might be able to keep several. Perhaps one in a BOB, kept charged with a 120v charger, and another in the car hooked up to a 12v recharger unit, about $10. For reliability a spare battery and hand-crank charger helps. A larger remote antenna can extend the range and is a nice option if your phone has a jack to hook it up.

This company has good service in almost all of Florida and has a pretty reliable service history even after hurricanes. But check your area for companies that cover it and ask around about reliability.

My preference is to get a phone that just acts as a phone. If the phone gets lost or destroyed I don't lose any important features. I try to avoid all-in-one type devices.