I have personally used a variety of Sat phones. Here's what I can tell you.

First of all, no sat phone works all the time, everywhere. Anyone who tells you they do is lying.

There's two broad classes of phone, the handheld (which is a BIG handheld) and the transportable phone (it can be in a a darn big case) and the fixed systems, which offer the most in terms of features and reliability.

All of them work fairly well, but sometimes you can't get a connection because of the line of sight to the sattelite not being right or the weather is funny. In some cases, for example, in a valley, you might only be able to use the phone for 30 minutes a day as the "bird" passes over.

There are workarounds, of course, it's a matter of money and size.

Your best best is to contact Robert B. Rosen rob@remotesatellite.com, he's an ethical guy with great support and a fantastic selection of products.