Early 2010 I purchased the QuietComfort 15 and despite the good noise reduction and lovely sound, for 350 euro's you'd expect it to last. In reality, the thing is falling apart. I did purchase some new ear-cushions ($44 a set) and realise I could have done this annually as they don't last at all. Just like the rest of it: one of the speakers stopped working. In sum: Love the sound. Hate the weak design. Would be very hesitant to purchase another set.

I have the older version of this and I like them. I only get about 8 hours out of the rechargeable battery. I'd much prefer the option of using a disposable aaa or aa battery that these use. However, if you are going to go through the trouble of making sure you have a battery in your headset, you might as well make it bluetooth as well. I won't be buying another headset until I can get both.

Just use rechargeable AA batteries. I have the Bose 15s and I've been using rechargeable NiMH AAA for years. As a programmer, I use them for about 5 hrs a day, and on the plane for on any vacations. I think I've had them for 4 yrs now and just did the cushion replacement - much less $$ for non-Bose. No issues at all. Love them. At least then you aren't stuck with a device whose internal rechargeable non-user-serviceable battery gets old. And in a pinch, you can always use a plain AA. Keeps it standard and gives you options! AmazonBasics NiMH are a good deal, and I'm sure there are plenty of others.

If you don't need noise canceling Audio-Technica ATH-M50 offer pretty solid sound quality for about $150 and a lot of people recomend them.

I must have an earlier version of these (but they look the same) because they don't work without a battery.
I love them! I've had a lot of top end headphones including Sennheiser (several), AKG, Sony professional, and others but these are my favourite by a long shot.
Immensely comfortable, incredible sound and with the amount I use them a battery lasts for months.

I have these, and I have 3 of the previous version, they all work very well. I have so many because my whole family wears them on flights.

from the description it sounds like they didn't much improve the sound quality of them at least when unpowered. in my experience, closed-back cans all have a "canned" coloration to the sound, a closed-in sound, like the headphone equivalent of "boxy." the best of all worlds would be if they let you select active equalizer sans noise reduction, and if they let you install a good rechargeable alkaline that lets you recharge it with the usb input. I also would like the option of cloth earpads, and the leather ones usually get slippery with my sweat in hot weather.

I've had the QC25's for the past 6+ months now and I can guarantee you the battery's AAA. :) I use Eneloops though and they last a fairly long time per charge. The ability to carry a spare in the case is an absolute must, because when it stops working, it does so without any warning whatsoever. (Wakes me up when I use them unplugged for noise cancelling alone at night to sleep.)

I have the QC15 version of these headphones that I bought in late 2012. The sound quality and noise cancellation is as great as this article outlines. I'm a woman with a small head though, so even on the smallest fitting, they're uncomfortable after an hour's use.
Despite the great sound, I won't be buying another Bose product ever again though. For the high price, you expect high quality, and yet Bose fail to deliver the end product.
The leather on my earpads started to disintegrate after about a year of light use, even though I took very good care of them (e.g. letting them dry off properly if they'd absorbed any moisture, always keeping them in their case, keeping the silica gel in the case to absorb any residual moisture). And I live in the Uk, where it's not even humid.
Once the cushions start to break down, it just wouldn't stop. The leather peels off in very small pieces that get stuck to your face, or fall on your clothes, so you can't really wear the headphones in public once they begin to breakdown.
The customer services team absolve all responsibility as the cushion pads are made of "a ‘potentially’ perishable" material and also highlight that as the cushions are a removable part, they aren't covered by the 2 year warranty anyway. They just want to sell you replacement cushions - but as DelaneyShanmugam explains, the new cushions don't last either. You end up throwing good money after bad.
So whilst Bose got the sound right, they failed on basic quality. And there is no after care service once you've paid for your item, they are just a sales team.
Only buy them if you have money to burn

I'm really happy that they upgraded the QC 15, though great audio and noise cancellation, the new QC25 really lives up to it's price tag and Bose's quality standards in design!