I've had the Sony MDR-NC50 for about a month now. Just got back from a trip to China. Although I havn't tried the Bose QC2, I can give you a little feedback on the Sony version.

Of course they are a little bulky as the ubit needs to cover your entire ear to be effective. With that in mind, the case that they come with is not too much bigger then the unit with allows for fairly easy storage and great proctection of the unit.

There is a little tightness around your ears with an extended amount of continuous use, as in over 2 hours straight, but that goes away with a slight movement of possition on your ears.

They give off a low frequency tone that "cancels" the wind noise in the body of the plane and most other constant sounds that are around. I thought they would do a better job of "canceling" the sound of people talking around me. You can still hear the flight attendant slightly when she asks you what you want to drink. So it doesn't completely get rid of all outside noises when you are listening to the unit at a lower volume. However, as expected, there are no outside noises when the volume is turned up past medium with most songs or DVD's.

The clarity of music played on the headset is superb. Very clear and crisp stereo surround quality.

The battery that cam with the unit lasted I would say about 50-55 hours of use time with the canceling function on. It helps that the case comes with a storage space for an extra battery. There is also room for a couple different speaker connection pieces in case a stereo uses a different input piece.

Overall, I would recommend this unit for long trips where it can be used for an extended amount of time. It may be a little bulky to carry around everywhere just to use with a small MP3 player or IPOD. Although there is space in the case that some MP3 players would fit and the case could be used to carry both the player and the headset. But without having tried the Bose unit, I can't give you much of a comparison.

-=TIM=-