Speaking of the Ping, I have an old one connected to my 740 by USB cable.  As of late all the altitudes displayed seem to be way off by thousands of feet.  As an example I was flying near my buddy who was at 4500' and it was displayed on the 740 as 8400'.  I have not kept up on the forum until now reading all I can about the Ping Buddy but apparently it has been discontinued and is no longer supported.  Would this have a factor in the erroneous altitude reports?  Is the Ping Buddy now worthless?
I wished I had known this as I just installed a Garmin GDL 82 (ADS-B out) and probably would have gone with the uAvionix echoUAT in/out bundle.
Thanks