Before I was aware of the UFM adapter I went to the Bose store to buy a pair of QC2's. They had a listening booth which would play all kinds of background noises so you could hear how well the noise canceling worked. Although I went in intending to by the QC2's I left with the QC3's as I felt they had superior performance. I also switched my QC3's with a friends QC2's on a flight once and both of us agreed that the QC3's performed better. I believe the reason for this is although they both have the same noise cancelation chipset in them, the QC3's memory foam seals the ear canal by filling the outer canals with foam whereas the QC2's attempt to seal on the head can be degraded by things like hair.