I have the K490NC. It's fairly neutral, and unlike most NC headphones, the NC effect doesn't really mess up the sound. I also have the MDR-NWNC200 which is made for the Sony Z Walkman (I have the Z1070) which uses the built-in NC of the Walkman in conjunction with the MDR-NWNC200. At the end of the day, the K490 does a decent job with NC. I feel the NWNC200s do a bit better job, but are also more uncomfortable for longer periods. The K490NC is more neutral and a bit bass-light in comparison, whereas the NWNC200 is a bit bloated but not bad for what it is. At the right price (I paid $250), the K490 is a pretty good deal. I'm curious to hear the K495 which supposedly has more bass but unlike the K490, not as good w/o the NC function turned on. I'm also intrigued by the upcoming Sony MDR-1RNC, but the K490 is a small and light headphone while the 1RNC looks MUCH bigger. Just as an FYI, I've tried it on planes and trains since I travel quite a bit.