I've owned and regularly used all of the Bose noise-cancelling headphones and recently got myself a pair of the QC 20i's. What can I say? If you are looking for something really small with decent sound quality and good noise-cancellation, these will be the ones to go for. I really like the design of all of the current Bose in-ear headphones, you hardly notice that you are wearing them at all and the earbuds don't have any tendency to fall out of the ear. Of course, due to the size of these babies, there are some drawbacks as far as the degree of noise-cancellation and sound quality goes, so these things will always be a compromise between the size and the sound quality. If you are into really great noise-cancellation and superior sound, get a pair of QC 15's, in that respect, they are much better than the QC 20's. If your main concern is size, the QC 20's are for you.