I went through two pairs of these in 18 months. Within the first year, I lost all sound in one ear, despite looking after them very well. Becuase they were in warrantly, Bose kindly replaced them free of charge. However, the EXACT same thing happened to the new pair a few months later, and this time, becuase the warranty (for some reason) ran from the original purchase, they refused to replace them. A friend of mine had the same problem with his, too. I asked about repairs only to be told that "It would cost more for us to repair them than to produce a new pair". If I'm spending £300 on a pair of headphones, I expect them to last years, rather than months, and I also expect a repair service, particularly if they are cheaply made in China (which these are).
The sound IS good, don't get me wrong. But not that good. They often sound a little muddy in the bass frequencies. I replaced these with a pair of the AIAIAI studio headphones and I have never looked back, but if I wanted noise cancelling I would go Seinhesser. Don't waste your money on these.