So if I'm reading Darryl and Mike correctly: The bottom-line is that
the different ADS-B options and reliance on ground-based coverage mean
that FLARM-to-FLARM communications are really the only solid solution
for collision-avoidance when close to terrain or out of ground-based-
coverage areas.

(Mike - before you reply and push the Navworx box yet again, please
prepare an explanation of how the Navworx unit gets around the very
same UAT versus 1090ES issue that you described moments ago. If UAT
and 1090ES don't talk to each other from aircraft-to-aircraft, then it
doesn't matter whether you run a powerFLARM or Navworx box - you're
going to miss out on some of the ADS-B traffic either way.)

--Noel