Just another headset data point - I used my friend's Bose X headsets (ships power, not battery powered) in his Mooney and I became convinced that at takeoff power they were "overpowered" by the noise and essentially quit.  Then when power was reduced they suddenly became quiet.  I don't know if it was my imagination or if anyone else has observed the same thing.  One thing I always liked about the Peltor (same as Sennheiser, I believe) is that the headband is very thin, giving me more headroom.