There is a good article by Practical Sailor this month comparing SPOT and similar devices to PLBs. Noteworthy quote, "While PLBs and ERIRBS must pass a demanding test of
electrical and
transmission tests to get COSPAS-SARSAT approval, SENDS ( I.e.SPOT) don't undergo the same level of scrutiny."
The more I read, the more my opinion is confirmed. SPOTS are nice toys, PLBs are nice
rescue devices.