“It is engineered to withstand the altitude and temperature conditions common in non-commercial aircraft.”
Nope; to me, that means that it's suitable for cold, low pressure environments such as found in unpressurised aircraft at altitude. What 'altitude and temperature' considerations are there in airliners? Normal room temperature and about 8000ft PA...
I've used many headsets in many aircraft, and the X is defintiely my headset of choice in both big and little jets and a variety of other things that I fly, without any problems.
My one criticism is that when changing seats, it's a faff to swap the mic boom over - I'd prefer a swing-over design, but that would mean the ear pieces weren't profiled for each side. This is a particular pain when swapping seats part way through a training day on a short turnaround.