I was using the Bose QC-2 headphones on the 744, but the headset cord is not insulated properly, (not TSO'd) and I was getting interference from the side window heat and other wires running up the corner post. Take that for whats its worth. I was vacillating on either the Telex 850 or the Lightspeed Zulu. I ended up with the Lightspeed Zulu for a couple of reasons. I'm trying to save whats left of my hearing and the noise cancelling is absolutely the BEST. Better than the Bose aviation sets!!!! Better than the Sennheiser!! Plus, it has a cool feature, you can plug your i-pod into it, and you won't miss a radio call because it cancels out the music when someone is yakkin, and it keeps you wide awake on the dark and stormy nights in the middle of nowhere while you other mate up front is noddin off! They're kinda spendy, but they are very comfy, and the audio is truly high fidelity. I have heard things with these headsets that I have never heard before from my i-pod.