Yes, a very good summary of EPIRBs, thank you QDM. No suprise that McMurdo weren't happy about the test results
I spoke to Sartech at the time of getting the Kannad non-GPS unit I have, and their view was that for normal UK/Europe (cross-channel over water) flying a GPS is not needed because the 400MHz satellite homing, combined with the low power 121.5 VDF signal, are sufficient for getting found reasonably fast. But outside the "civilised world" one may be relying solely on commercial shipping for SAR and a GPS EPIRB is essential.