I have these headphones for over six months now and all I can say about them is that they are really unbelievable! These headphones were first made for F16 pilots to preserve their hearing ability by lessening the wind noise they get during take off and landing. Saying that these do it very well is an understatement!
First off, I would like to say that Bose should change the name from Noise Cancelling to Noise Reducing because I can still here the warning tones by the captain during in-flight, which is a good thing. Also, these only reduce the sounds made by other people who talk excessively loud. I consider them as noise, but they don't get cancelled. (I even wrote a blog about that.) Other than that, I have no complaints at all!
These headphones give the best sound experience ever! When you put them on, you feel like you are part of the music, as if you are watching the musicians live. You also get to notice the little quirks of the music, such as the lead guitar is panned to the left, the tambourines are somewhat panned to the right.
I know that these will make a huge dent in your pockets but it is really worth every penny especially if you are a frequent flyer or a snotty musician (such as myself) who likes to scrutinize every detail of the songs being played.