Bose QuietComfort 2 Headphones

I am just about to start my third pair of QC2 headphones in 3 years. I use them on flights quite frequently. The sound quality is very acceptable for in flight as well as MP3/4 and Computer/DVD. There is a thoughtful impedance switch to alter input setting for airline use which some others do not have. The noise canceling is very effective with bass roar from engines but less with middle frequency air noise. They do provide a welcome relief from annoying children and babies though. The unit runs on AAA battery so you cannot get caught with no power as on QC3's. The units has three downsides for me, in ascending order of importance: Bulky in case, they howl with feedback if you accidentally fall asleep and cover one earpiece by putting your ear to a pillow, they fall apart. I have had two units fail now. The original problem they said was a design flaw, now it looks like a plastic weakness. Both times, I picked them out of the case and they fell apart in my hands. Never had this with the Sony's but prefer Bose sound so now going to try Sennheiser PXC-350.