As far as sound goes, like with the QuietComfort 2s, the first thing we noticed when we put the QuietComfort 3s on was the bass. The new model, in fact, offers fuller bass balance; it's richer, warmer, and plumper, though it isn't as detailed. That kind of bass--and overall sound--is appealing on hip-hop tracks, but it can be a little overpronounced on acoustic jazz pieces, for example. In other words, these guys sound big--you won't mistake them for smaller headphones--but they aren't incredibly clean. And one other small thing worth noting: the QuietComfort 3s are less sensitive and don't play quite as loud as QuietComfort 2s. It's a small difference and shouldn't be a factor with the vast majority of portable music devices and movie players, but it's one reason that especially attentive listeners may wish to opt for (or stick with) the older, larger models.
In the end, if you're trying to decide between these headphones and the QuietComfort 2s, we can only say the choice isn't easy. The smaller form factor and rechargeable battery are definite pluses in favor of the Bose QuietComfort 3s, but the more refined sound and the over-the-ear design of the QuietComfort 2s have their appeal. If money is no object, you can't go wrong with either model, but ideally, we'd like to see the company drop the price on the QuietComfort 3s and QuietComfort 2s to $299 and $249, respectively. We think $350 is a lot to pay for headphones, even those with a rechargeable battery.
Steve Guttenberg contributed to this review.