The Spot Sat phone must be a new service from Spot. When Delorme's "in reach" came out I gave both Spot and DeLorme serious research, and checked them out again this spring. At that point Spot was not offering a Satellite phone product. This new offering seems to me to be in direct response to Iridium's contract with DeLorme and DeLorme's development of "in reach."
I state this simply to let you know there may not be all that many people out there who have tried the Spot Sat phone as it is likely a very new product. (Your post was the one that sent me to their web site to find it).