For what's it's worth, I rented an Iridium 9555 phone this summer. Never dropped a call Hawaii and back (well, once or twice during a squall). Much (much!) better than the old Inmarsat Isatphone Pro.
The key for me was the auxiliary "fixed mast antenna" (buoy antenna), which I mounted on a vertical length of PVC pipe on the stern railing, and ran the long included wire under the cockpit to the nav station. Indoor talking! No more phone tucked under a foulie hood while facing the equator in 30 knots and shouting "say again?"
I looked at the Go, which requires an iPhone for voice calls. If abandoning the boat I figured grabbing a waterproof Iridium handset would be sorta easier.
I sent emails with KML (for Google Earth) files by hooking the handset up to a laptop with a $30 hockey-puck USB GPS, compression through UUPlus.
I rented from
http://www.satstar.com, after being told they were good on personal response and so on. I'd use them again. In my opinion, rental is the way to go for a satphone.