The advantage of Power Flarm and one or two others is that it combines technologies. You get ADS-B (which will eventually be the standard in 10 – 20 years) plus transponder detection (mode S + C maybe) plus Flarm. Power Flarm is over a year late and the specs have been a bit fluid, so we will see. On big advantage is it works at greater range than std Flarm which is better for higher speed aircraft.
Chris and I have tried to raise the collision avoidance issue and we have had some limited input into some of the specs for devices following various articles in Flyer and Gliding mags.
Rod1