...the Bose X. It is sold with a 30 day return if you're not satisfied - suffice to say I was not. Very overpriced and unsatisfactory at higher frequencies
Quite untrue.
I've been using them for eight years. I have also tried every headset in a particular headset shop, against an aircraft noise source.
The only one which came close was a ~£500 D-Clark model but with a vice like grip on one's head.
The other, cheaper, ones were just crap in comparison. I used to have a Pilot DC17-79 which was utter crap; it even whistled sometimes. The ANR performance was rubbish. I returned it to Pilot in the USA who confirmed it was in spec!
Protecting one's hearing, never mind actually hearing ATC, is worth paying extra for.
Still, listening (when flying) to the crap quality of peoples' radios, and amazingly often the crap quality of ATC microphones (and probably other equipment), I am not suprised people don't want to spend the money.
I have heard that the Lightspeed Zulu gets quite close to the Bose X. I was going to try one in the USA recently but nobody had any stock. They also do an aircraft powered version with the same Lemo plug as the Bose aircraft powered version has, which is a smart marketing move.