I have used the PingBuddy several times now and it appears to be working. Based at South Albany, we flew down to Sky Acres and saw a lot of traffic. On the way back, almost nothing; I think that the proximity to big plane SWF activated the ADSB towers, but nothing between there and Albany, where there is not much traffic. On another note, flying north of ALB, I was surprised to see ADSB towers displayed on the 740! Cool. And the airport weather is just the best, will help a lot on the way down to Lakeland.
My 740 has a ship's power connection with a 2 amp breaker - no problems. I use the 740 USB to power the PingBuddy. Had to get a longer cable so the PB can get closer to the windscreen. Make sure the cable is MicroUSB "B", not the MiniUSB; they look almost identical. Don't ask how I know.
Still trying to find a legend on the traffic display. Are the altitudes shown MSL or relative to my altitude? Also the + and - signs led me to believe the altitudes are the latter, but not sure.