The noise-cancelling performance when you turn on the battry pack has to be experienced to be believed.
I do wonder about this......is it real or just percived? Most headsets have very good passive annuncation, and the ANR on them simply is the cherry on the cake....it adds a little more, to the already good annuncation. So when you switch on the ANR, you get a little less noise, but nothing earth shattering. Your annuncation goes in two steps....1. Putting on the headset, and 2. Turning on the ANR.
On the Bose X the passive annuncation isn't great at all, but the ANR does an excellent job when you turn it on. The effect is dramatic, because it goes from very little annucation to very good in one jump.
Having used both the Bose and DC's I don't think the Bose X has any better annuncation than my current headset (DC20-10XL)....but the effect of turning on the ANR on the Bose is much more dramatic, than on the DC's. Bose don't produce any figures for their annuncation, and I presume this is because it would show that their annuncation isn't any better than anyone else's.....it's just a matter of perception. Which ever seeing those figures, it will remain just a guess, but that's my take on it.
Comfort is another issue though. I accept that the DC20-10XL's that I use are much more comfortable than most of the other DC's, but the only significant advantage that the Bose has over them in terms of comfort is the fact that the Bose is smaller and lighter in weight. Both are quite comfortable to wear for awhile, although as I say, I do accept that most DC's have a much higher clamping force than I'm used to on the 20-10XL's.
You pay your money and take your choice. At the end of the day, I've yet to come across someone who bought the Bose and was unhappy with them, which does say a lot. If you intend flying long term, then buy the best headset that you can afford. When I bought my headset in 2002 (Just out of warrenty this summer!) they were significantly more expensive than the Bose are now. But I've had five years of excellent use, without any problems. The headset looks and functions as it did the day I got it. I've no reason to suspect I won't get another 5 years of happy use. Writting the cost off over ten years (perhaps more) means that the cost really isn't a big factor in your flying. So pay for the best you can affort (rather then the best you can justify). Otherwise you'll spend years wishing you'd forked out the extra
dp