Telex Stratus 50D, claimed to be on par with the Bose, though no personal experience for comparison. Overall very comfortable 5-6 hours straight, but eats batteries (I use rechargeable) unfortunately, unless you have the panel powered version. Either way, it'll do a very good job as a passive headset also.
Minor gripes other than the battery life, occasionally the mic senses the noise slightly off (for example when having one window open in the cockpit during taxi etc., yeah I know, no pressurized a/c for me yet...) causing a minor vibration in one earphone, until the "system" figures out the correct balance. That's as far as I can go with this digital-noice-cancellation-technology-mambojambo.
I'll measure the bang-for-the-buck when I'm 60 and hopefully not wearing a hearing aid. Worth the top-dolla for me so far, highly recommend them.
T