They are comfortable, they look nice, they have an input for an MP3 player/mobile (if that is safe/legal where you use them), they're green.
The ANR bit (which is the bit you're paying for) isn't much cop. It takes out just a bit of the rumble, and that's about it - really crap. It actually injects a bit of high frequency hiss when you turn on the ANR. Complete and utter waste of money.
Notice the absence of dbA data on the headphones in the literature/adverts. That should concern you.
Save your money, use a pair of soft earplugs with a standard headset if need be, and enjoy the £500 on something else (like eight hours flying).
T.