I am a bit of an audiophile, and sound quality is important to me, as is style, performance, and of course price. These phones manage to brilliantly balance all of these factors, in a stylish design.
The sound quality is wonderfuly open, balanced, detailed and clear. Used with my iPod touch with equalizer set to 'Flat' the bass is perfect in a product like this, ie detailed and not too thick and deep, and the treble is open and sweet!
The noise reduction is very effective, though not as good as say the Bose QC3's, which I have owned. There is a noticeable hiss (significantly more than with the Bose phones) but it is the case that you would only turn on the circuitry in a noisy environment, when the hiss 'effect' seems to dissappear, and you truly benefit from significant reduction in low level ambient and annoying noise. You would hear some hiss in a quiet environment (which you hardly do with the Bose phones) but in this circumstance you can just turn of the noise cancelling, and they operate as a normal pair of good quality headphones (which the Bose phones don't).
So, if you want top notch noise reduction but thick and woolly bass reproduction (and don't mind paying over £300 pounds!!) go for the Bose QC3's. But, if you want top quality sound, smart design, portability, along with very good noise reduction (when used in appropriate situations), and want all of this for about £60 pounds only, definitely get the Sony's!!
A perfect balance of all factors in my view. Highly recommended!!