I've got the Zulu.2's, I traded in a pair of Lightspeed 30-3G's that I had bought used. I was completely satisfied with the 30-3G's and was actually planning on keeping them for the long haul. Unfortunately the plastic headband broke in half one cold winter day as I put them on.
That was a noisy flight home. I realized NONE of the aviators on Flying Wild Alaska or Ice Pilots: NWT were using 30-3G's, if they had Lightspeeds, they were the Zulu model. So valuing my hearing over my pocketbook, I splurged for the Zulu.2's over the Sierras.
All-in, I spent around $750 out of pocket to get the Zulu.2's. Not a bargain by any stretch but better than paying full retail. No regrets.
I do have some criticisms of the Zulu.2's. The control box seems a little cheesy, not quite fitting with a $900 MSRP product, in particular the plug wires are a little skimpy looking compared to David Clark headsets. The microphone is directional, but there is no super obvious microphone orientation marking. I probably flew 10 hours with the Zulu.2's shouting into the mic as a result. One of the most glaring problems with the audio is the obvious hissing you can hear in the background when listening to music via Bluetooth-phone connection. I know that ANR is almost like a black art, but it's a little dissapointing that these headsets don't also double as audiophile quality headphones. The Zulu.2's are only good in enclosed cockpits. I get a burble of wind noise with the window open, I don't think they'd be very good at all in an open cockpit plane. Lastly, the omission by Lightspeed of a corresponding Android phone application stings a little--it makes me feel ignored by a company I otherwise want to like.
I tried the Zulu PFX at Oshkosh and liked them--especially the new wiring and the aesthetically improved control box. They seemed quieter but the annoying droning noise generated in the Lightspeed tent is nowhere near as loud as my plane. I wasn't able to compare the PFX and the Zulu.2 side-by-side... I did feel a little bit of buyer's remorse on the Zulu.2's after trying the PFX.
I was also very impressed by the Sennheiser S1 ANR, especially the passive protection and the enhanced ANR achieved through "pressing the button". I think the new Lightspeed PFX has a similar but more transparent implementation of that adaptive ANR technology.
If I wasn't already $750~ deep into my Zulu.2's, I'd be tempted to buy the Sennheiser S1 ANR's.