I would be interested to hear any comments on the Lightspeed Zulu headsets.
The best thing you can do is actually GO somewhere and try them out. My local dealer had a sound cabinet to simulate different environments (GA open cabin, 1 Mot, 2 Mot, turbine, Heli etc) and you could then judge the individual sets.
I went there thinking to buy a Sennheiser or perhaps Bose but the Lightspeed Zulu fitted best to my head, the Sennheiser sort of "perched" on it, DCs clamped my head tight and Bose seemed to crush my ears. I ended up buying the Lightspeed Zulu, have since upgraded to Zulu.2 but didn't see much difference to the Bose - except when viewing cost and Bluetooth capabilities.....