Recently got myself a set of MDR-1RNC MK2's for $460 here in Australia and they are fairly good, but they aren't worth their price. The sound quality is very good in the mids and highs, very crisp and clear (with NC on). However the bass and sub bass are both lacking. They are there, but they are not impressive at all and have no impact, which is surprising to me as they have 50mm drivers, so bass should be fairly good. Nowhere near as good in bass as the 1R-MK2. When the noise cancelling is off, the sound is just wrong, the clarity just disappears, making vocals sound horrible, so I just keep noise cancelling on to avoid it.
Noise cancelling is quite good, blocks out most ambient noise and helps keep my daily commutes quieter.
I quite like the build quality as it is a step up from the 1R-MK2 and 1RBT-MK2, with less plastic and more metal used. The cable is nice and thick, feels quite sturdy and because I don't live in a cold climate, I don't need to worry about cable stiffening in cold weather. The headphones are fairly comfortable, the headband disappears on my head after a short while, but they aren't as comfortable as the 1R-MK2 and 1RBT-MK2.
Overall, the 1RNC-MK2 is a good headphone, but not worth the price. My advice if you do go and buy a pair, keep the noise cancelling on.