Single Status Update
Just had a chance to listen to the Bose QC25s (wired version of the famous QC35 for half the price) and definitely have mixed feelings.
One surprise was the sound quality varies significantly between noise cancelling on vs off, and probably not in the way you'd guess. With that in mind there needs to be two separate sound reviews:
With NC on, I'd describe the sound as poor. Clarity? What's that? You can certainly find superior performance for 1/4 the price, that I have no question of. But, they are passable as headphones...
...which is more than I can say for the sound when NC is off. My god, I've actually never heard anything that shitty before. It's like listening through earplugs, or to a stereo with your hands over your ears or something. Even free earbuds are more "present" and clear, though these do have more bass, as if that matters in comparison (it doesn't). Hard pass from me, literally a worthless listening experience.
The noise cancellation itself is quite good though, which I guess is what you're paying for, but I'm not sure they make a whole lot of sense as an overall package. For one, as closed back, inherently isolating, "passive noise cancelling" headphones, they're really not great. There are definitely more closed sets out there. On top of that the ear pad material, combined with the fit makes them never feel "settled", or comfortably clamped to your head, always just resting on it in a way that lets any movement remind you how fleeting of an interaction it will be. Personally, with that in mind I think you'd be better off foregoing the active NC in favour of just blocking more sound passively and sounding a lot better to boot. You might get a bit more noise let in, but at least it'll be in the background of your enjoyable music. With these, the silence just lets you focus on how poor the music sounds.