Spot has tried to address some of the issues M_M mentioned, but it still has some bugs. I know guys had problems with the 1st ones, like not knowing if their message was sent. Spot added a "message sent" light to the new ones, but it comes on while it's still "sending". It doesn't mean the message is done sending  ::) Oops
Engineers need to try again "issue 3"  ;D

Spot did cover the buttons better as M_T says. And there's two "I'm OK" buttons, so there's more options for coded messages like "I got my Elk. Come help me pack it out."

My opinion is Spot is more for fun, comfort for contacting those at home, and maybe taunting some friends that didn't get to go  ;)

Really reliable SOS help is the PLB.