I have read all the reviews and don't really buy all the bashing by anal audiophiles on the Bose headsets. They deserve it for other things, but not these. I have tried several different noise canceling headphones and kept returning to the Bose. The QC-15 canceling ability is significantly better than the QC-2 it replaced. But surprising enough it also suppresses cabin conversation another probably 10db over the QC-2 or the Sony. Actually too much unless there's a 4 yr old next to you.
If you want QUIET, you need to go for earbuds. I had a pair of NC Sony's that were so quiet you could hear yourself breathe sitting behind the wing on a 737.