Great discussion. I have had the OceanSignal flare for several years and their stuff is awesome. I also spent about an hour at the Annapolis boat show BS'ing with the rep and learned a lot about why things are the way they are. The PLB vs MOB debate is a good one. I did ask the rep why they did not combine them and there were a couple of issues so we are stuff with having to choose for now. My thought is that is you are in the Chesapeake Bay or a similar body get the PLB; if in the ocean you need the PLB. FWIW, I worked on an upgrade of the NOAA/NESDIS COSPAS/SARSAT system 16 years ago and DLochner has the process about nailed on how it works. It is not super fast or efficient but it will work; AIS will get the attention of every boat with in a couple of miles and with the USCG Rescue21 upgrade to their VHF communications they will most certainly hear it as well. Since both systems communications are digitally based and they repeat there is really no chance they will not get the message and your location. DrJudyBs testing of the radio confirms that relying on a handheld VHF in the water is likely to not work; especially when you consider VHF is line of sight and you and the radio are in the water.