I've been looking into, reading reviews of the Spot for a while now and not sure what to think of it at all like Yuccahead post states. I've been thinking of buying one and trying a month service and see how the unit works and if not happy returing it.

I'm planning a 17 day back country canoe trip in Nov of this year in the Everglades.
There is no cell service available there.
What I like really like with the Spot is the I'm OK messages it can send. This way family members know that all is well when there is no way to communicate with them.

I also thought about seeing if it was possible to rent a PLB, but then family members would have no idea that I'm ok and would be out of touch for that time and make them nervous.... unless I get a Spot and it is possible to rent a PLB.

Are there places that rent PLB? Just answered this myself, Yes.
Is a messaging system to family members something that PLB manufacture companies are looking into at all?