I compared these headphones side-by-side with five other noise cancelling headphones: Bose QC2 & 3, JVC NC250, Audio Technica ANC7, and Sennheiser PXC-250. My main criteria were sound quality, noise cancelling, and comfort. The only headphone that excelled at all three was the PXC-450. I disqualified all but the PXC-450 on the basis of out of the box testing.

Bass. When I first put these headphones on, I admit that I was a little let down because it seemed to me like they were very weak. Then I realized that I needed to adjust the volume control on the headphones. With the volume issue fixed, my concerns about the bass went away. These headphones do not have as much bass as Bose. However, that's because Bose changes the sound from the way it was intended to push the bass forward. If you like a lot of bass, these headphones might not be for you. However, the bass is definitely there. Just listen to Pon de Replay (Rihanna) or Pass that Dutch (Missy Elliot) for a demonstration of how good the bass is on these headphones.

Sound Quality. Moving past the bass to sound quality as a whole, these headphones are in a different league. I mean, I am hearing details in songs I have heard dozens or even hundreds of times and never noticed. Background singers that before were lost with all of the other sounds can be heard clearly on these headphones.

Noise Cancelling. These headphones have a tight fit, which gives them a lot of passive noise cancelling. They are not so tight, however, to become uncomfortable. Combined with the active noise cancelling, and these headphones are *almost* as good as the QC3s. I feel like the QC3s were a little better at cancelling the higher frequencies, but I think that is why they have the pressure on the eardrum problem. I didn't feel any pressure with the 450. The slight advantage the QC3s have on noice cancelling is more than outweighed by the 450s superiority in sound quality and comfort.

Comfort. Despite being snug, the 450s are very comfortable. The material that the earpads are made of is very soft and I quickly forgot I was wearing them on my flight. The headphones are very big--much larger than the on ear QC3s. However, because they are snug they don't slide around and they really do melt into your head after a while. Also, they don't get hot like the QC2s did.

Portability. Because they are bigger, they are slightly more difficult to manage than the Bose. However, they fold up quite nicely and their case, though larger than both of the Bose cases, is still rather small (and light!).

In the end, once I tried the 450s, there was really no way I could settle for any of the other headphones I tried. All of the other headphones had too many flaws and the 450s were near perfect. Oh, I should mention that I listened for the "ticking sound" that other reviewers complained about in the right earpiece and there was absolutely nothing. Either those reviewers had defective units or Sennheiser has fixed the problem.