Used the new B&O headphones on AA72 SYD-LAX yesterday when my Bose QC35's ran out of power. They initially had this nails-on-a-chalkboard screeching sound — probably defective wiring in the left speaker — which went away eventually. Aside from that, I thought the ambient noise cancellation to be okay but the comfort to be a hinderance: my small ears just did not fit wholly inside of them the same way they do with Bose headphones. This became pretty uncomfortable and I stopped using them as a result.