I have a Bose QC2. I've owned it for 4 maybe 5 years. It was a very generous gift. I've used it on 3 maybe 4 flights. I got an IEM by Ultimate Ears, never used the Bose again.
The QC2 is comfortable, the QC3 since it presses on your outer ear -not so comfortable. However, the sound sucks. I abandoned the QC2 and let my GF use it. After trying the Ultimate Ears IEM, she abandoned the QC2 as well. Here's a totally honest assessment from a non Head-Fier - "The Bose sounds really hollow".
If you are into comfort and noise isolation, the QC2 will suffice. If you want great audiophile-level sound quality on top of this, look elsewhere.
The QC series suffer from acoustic reverberation common in poorly-implemented closed/semi-closed headphones - this contributes to the "hollow" sound. It's like putting a seashell to your ear to hear the ocean effect. Bass, Vocal/Mid and Highs are poorly defined in the QC series.
However, the Bose QC is a huge step up from using iBuds on an airplane. And the brand recognition will have cachet with some people you may or may not care to impress.
If you have to go with the same form factor, the Audio-Technica ATH-ANC7 sounds much, much better and is just as comfortable, though I only tried it in the store and not on a plane:
Under $145 from amazon.com
There are many non-Bose but great-sounding options for peace and quiet or music on an airplane. A summary of such options can be found here:
Traveling - HeadRoom - Right Between Your Ears
Bose truly sucks, and even the products that suck less have an unacceptable price given the many better options. For some, Bose is a true upgrade from that which sucks even more (e.g. iBuds). There are many better options that cost less, as well as tremendously better options that cost several times more than Bose.