I've got the Kaito, which is really nice to grab weatherfax paired with an iPad (though it takes forever). In less than half the time to get one weatherfax I can grab half a dozen text forecasts, the same image as in the weatherfax and a grib or two. But it is free and you can always get an image, even if the quality is poor.
Looked at the Iridium Go but decided against it. It would be wonderful to be able to use my iPhone to send relatively inexpensive text messages offshore. But counting on it as a piece of safety gear, the iPhone (or any smartphone/laptop/tablet) just isn't rugged enough for carrying into a liferaft. And even if you got it there without destroying it the battery would be dead in a few hours.