[This review was collected as part of a promotion.] When I first put these in my ears, and flipped the ANC on, I was in shock. Bose managed to outdo themselves entirely. I've been using QC Series headphones since my first pair of QC15 many years ago, and I can't believe how far earbuds have come along. Background sounds just disappear, and are replaced with rich, full, clear, impressive sound. These little earbuds sound like full-sized headphones, but they're so light and comfortable, they just disappear. I have even put them in my ears at bed time and fallen asleep listening to podcasts. I have quite the collection of Bose headphones, and these may just be my absolute favorite I've ever had. A++