These won't stack up to the most expensive, beefy models by Bose and others in the noise-canceling department, but do come out ahead of others I have tried in their price range. These are noticeably better at noise-canceling than many other models I have tried and I was really surprised by that - I had expected poor performance because of the low price. The sound is also quite good. All the nuances of the soundtracks to Avatar, The Hurt Locker, and Crazy Heart came through clearly and beautifully.
I have had issues with other noise-canceling headsets in the past - for whatever reason, they gave me headaches. Perhaps they gripped the head too tight, perhaps the canceling technology wasn't perfect. But the Panasonics had none of those problems. I have used these so far on three 8+ hour flights and thoroughly enjoyed having them. Positioned properly, the noise-canceling nearly canceled out the jet engines completely and I certainly couldn't hear any other people on the plane!
I like that they fold flat for front-pocket storage and come with airplane adapter. I also liked the momentary shut-off button so I could hear flight attendants. All in all, a very quality pair of headphones, quite unbelievable at this price point.