Hi Gypsy_Air
The Bose X has very poor passive attenuation when compared to (almost) any other ANR headset out there. This basically means that the earcups let in more noise. Ask anyone that uses one what it sounds like with the ANR turned off and if they are being honest they will tell you it is LOUD!
Now the ANR only tunes out certain frequencies ranges, but not all of the frequencies that you should be able to hear. Net result is hearing damage in the frequency ranges not filtered out by the ANR.
For anyone looking to buy a headset I would suggest you not only try one before buying, but also spend some time looking at the specification sheets. In particular look at passive dB attenuation figures and the frequency ranges that the ANR tunes out.
Sure, the Bose is probably the most comfortable, but that is partly because it has less clamping force and smaller ear cups. This design "comfort" results in a headset that then fails with it's primary task i.e. protecting your hearing.