I traded my Zulu 2 for the PFX at Oshkosh and was very disappointed until I received a call from the factory saying they needed to do a software update. I sent them to the factory and they were returned a week later. They work great now......better than the Zulu 2 set I had. Apparently there were some bugs in the software and they have been fixed.
I was confused about those lettered headsets. Mine is AKG not PFX, and I much prefer it to the Bose. I have both in my bird and my wife makes me where the Bose when she is with me; and solo I opt for AKG.
I traded my Zulu 2's in for the PFX and wonder why I did it. They seem to do an adequate (comparable) job to the Zulu's, but on take-off they range from working to no sound dampening at all. Very distracting. Light speed sent a new head cushion (thicker foam) and did some work on them when I returned them. But the problem persists. At this point, I don't know which option is best.