I have both the BOSE Quiet Comfort 2 and Sennheiser PXC250 noise cancelling headphones and thought I'd post my opinions and thoughts on them. Firstly the BOSE headphones.. These are extremely comfortable in my opinion, and the over the ear fit helps with the noise reduction. I have used these with my iRiver MP3 player and Panasonic portable DVD player, and in both cases find the sound results more than acceptable. Having to have them switched on even if noise cancelling is not required is annoying but battery life seems very good. I've had over 30-40 hours of use and have yet to change the battery. But will probably change next week before my next trip just to make sure I do not have any problems. Getting back to the comfort issue for a second. I used to use in ear headphones but found even expensive ones uncomfortable for extended use, and started only using over ear on on ear types for improved comfort. Last week I watched the first two Lord Of The Rings films (extended) on the same day using these whilst travelling and had no discomfort at all, my ears had none of the soreness I've experienced with other headphones. As for the pressure issue I read about, there is a slight pressure generated but it never got too much and I really only noticed as I was particularly looking out for it. I found the single cable entry very convenient compared to headphines with cables going to both left and right. Whether watching a film or listening to music these gave good results. I find the build quality to be good and overall I do not regret spending the money. Ok, now the Sennheisers. I had these first and have used them a little bit more. Comfort is pretty good with these, and still far better for me than in ear type units. However, I personally do not find the on ear design as comfortable for longer durations. You get a similiar pressure sensation with these, but again I did not find this irritating or particulary noteworthy. But that could just be me, others may be more sensitive to this issue. These were also more prone to windnoise in my opinion than the Bose units, and wearing outside or in enviroments with lots of moving air the noise cancelling does seem to pick up on this, not too much but thought it worth mentioning. Battery life is equally good with these, and aided by the fact you can choose to switch the noise cancelling off if the situation permits. My biggest gripe with these is the amount of cables I end up with. Whilst the headphones are nice and portable and fold up, you do have seperate cables for left and right, add to this the external box containing the power and on/off switch and you suddenly have a lot of trailing wires. Maybe I'm just being critical, but it has annoyed me at times. Again these gace good results for both music and films. Although I feel more background noise got through on these due to the earpiece design. Conclusions. Overall I personally like the BOSE QC2's better, and for any travelling that has me on trains or planes for a long while these would be my unit of choice to take with me. However, for shorter commuter journeys on train or tube I'll use the Sennheisers as they are more compact to carry along with my other tools and equipment. Both units come with good travel cases to protect them when in a bag or pack. If I had to recommend just one of these, it would be a tough decision, but ultimately I reckon the BOSE Quiet Comfort 2 headphones would win. They are comfortable, give good sound and I feel are well built. I do not agree with the build quality issues I have read elesewhere, and my experience is they have survived being dropped and pulled on my head and still worked. Yes, they are expensive, but for me worth every penny. Of course all the above is only my opinion but hope it helps if anyone is looking at these.