There are certain items that automatically trigger MCR in climbers. That's mammalian covet reflex for you non-science-y types. Satellite phones definitely fall into that category. Who wouldn't want the convenience, logistical advantage and extra margin of safety provided by a satphone? Not to mention the cool factor.
Iridium provides all that and more with the shock and water resistant and dustproof Extreme 9575 satphone, 9 ounces of black-clad ruggetude. I had the opportunity to take one up Denali earlier this year and it performed as advertised, providing a welcome communications line to family and friends and a back-of-the-mind reassurance in case of certain emergencies.
The Extreme connects relatively quickly, gives lat/long coordinates, sends text messages and even has a panic button that will fire off a pre-planned message to a given contact. Perhaps the feature I used most often was the lat/long functionality, where as I reached camp each evening I acquired a signal and texted the lat/long to my wife, who could click on the link and map my position, thus knowing right away which camp I had reached. I used a Brunton Solaris USB solar charger and the included hot shoe to recharge it (and a GPS watch and a camera) every day and it was no problem.
There is a complete array of additional functionality such as data tethering, mobile wifi hotspots, and various accessories such as external antennas, including a suction-cup antenna that will affix to an aircraft window. The only real downside of course is cost. You're looking at dollars-per-minute generally with most plans, but if you use it for only brief calls to home and mostly keep it in reserve for true emergencies and critical updates (e.g. park service weather reports) the cost is manageable. The Iridium phones are popular enough that you can find them for rental many places.
There is one other potential downside: the ability to power up and make a call is always right there, kind of like the impulse to check email or text on a cell phone. It can be distracting, and more insidiously it can increase feelings of loneliness and separation that can work on your motivation. These issues can be dealt with by having a pre-determined comms plan worked out with your team so that everyone knows where and when satphone calls are on the schedule, leaving the rest of the time to do what you came for. That said, we stand by our original declaration: it's pretty damn cool!