I actually traded in the QC2's for the 15s and while they are quite a bit quieter, they don't seem to seal as well and I get a lot of feedback on take off and taxi. It was enough of a problem that I could hear the ANR trying to compensate just chewing on something. Never had that with the 2s. I'm going to exchange them for a different pair and try that. If it's the same, then I'll trade em back for the QC2s again. On the plus side, Bose's CS is so far excellent.