The Good: Extra-comfortable design; clearer, more dynamic sound; highly effective noise-canceling circuitry that's been slightly improved; new folding design allows the headphones to fit in a smaller carrying case; if the battery dies, the music now doesn't die; 21- to 30-day risk-free home trial. The Bad: Fairly pricey. The Bottom Line: The QuietComfort 25 model takes Bose's already stellar noise-canceling headphones and levels them up to new heights. \t \tIf you're wondering how much better the QuietComfort 25 than the , the model it replaces, that's hard to quantify. But one thing is certain: it is better. \t \tWhile the two models bear a strong familial resemblance, Bose says the QC25 headphones -- which cost $300 in the US, \u00a3270 in the UK, and AU$400 in Australia -- are totally redesigned, with better audio performance and noise reduction, plus an improved folding design that allows them to fit in a more compact carrying case. \t \tAnother small but significant change is the shape of the headband. Bose has re-engineered it to sit closer to the head, so there's less of a gap under the headband. And it's worth mentioning the headband is covered in an "engineered fabric found in high-end automotive applications." The soft, leather ear cushions have the same luxurious feel of their predecessors and Bose says the hinge or "pivot" in the earcups is made out of "cast-zinc." \t \t \tI can't say the QC25 is any more comfortable than the QC15, but like that model, this is a very comfortable headphone. It does seem a bit sturdier overall, with a thicker detachable cord. Also, the aforementioned cast-zinc hinge seems well-designed. \t \tThere's still a lot of plastic involved in the construction, but Bose appears to have struck a good balance between durability, weight, and comfort level. Yes, the headphones could be even more durable, but they would become too heavy. This model (without cable) weighs 6.9 ounces or 196 grams. By comparison the weighs 9.17 ounces or 260 grams. \t \t \tLike the QC15, the QC25 is powered by a single AAA battery that delivers up to 35 hours of use. But what's new is that if the battery dies, the music plays on. The sound is a little weird without power -- "stunted" is probably the best way to describe it -- but at least you can get sound out of the QC25 if, for instance, it dies in the middle of a long flight. (I really wouldn't listen to it in this mode unless I had to). \t \tIn terms of extras, you get an inline remote and mic for taking calls with recent iPod, iPhone, and iPad models, as well as "select" smartphones. The long and short of it is some of the remote features may not work with Android and Windows devices but the microphone will (call quality was good). \t \t \tThe case seems to be about 30 percent smaller than the QC15's case. It's about as small as you get for a pair of full-size over-ear headphones -- but if you're looking for noise-canceling headphones that take up almost no room in a bag, the in-ear 'buds are the way to go. \t \tThat said, I did appreciate that the QC 25's case has slots for storing an extra battery as well as the included two-prong adapter for airplane use. Also, inside the case there's a diagram for how the headphones should be folded to fit inside the case (take my word, it's helpful). And it's great that Bose put a large "R" and "L" on the inside of the earcups so you can quickly figure out which is which. \t \tAnother great "feature" of these headphones is Bose's satisfaction guarantee. If you're not totally satisfied, you can return the headphones (or pretty much any Bose product) for a full refund. The trial period is 30 days in the US and UK, 21 days in Australia.