But the QC20s do such a good job cancelling out environmental noise that you completely lose track of your environment; I found myself easily startled by nearby movements

I think I can wear them indefinitely without any discomfort!They also do a solid job of noise cancelling, particularly in environments with a lot of constant, low-level noise such as an airplane

Picked up a pair for my recent trip to Argentina - did a wonderful job of drowning out plane noise and the unhappy young children for the 23 total hours of flight time

great job on noise cancelling, and the fit very comfortably in teh ear.

They do a good job of cutting out the background noise on flights and in the office

I see no way around this with noise cancelling headphones, and Bose has done as good a job as can be expected

These do the job quite well.

They do a good job of cancelling ambient

They are comfortable, stylish, and do a great job at canceling outside noise

But the QC20s do such a good job cancelling out environmental noise that you completely lose track of your environment; I found myself easily startled by nearby movements

The headphones work as advertised and do a great job.

They do a great job of cancelling out the very loud road noise from the dual-sport/dirt bike tires I use.