They're circumaural, so they sit comfortably on the sides of your head rather than mashing your pinnae flat, and their velour pads are nicely breathable; they also mass only a quarter kilogram (260g), and they're an open-back design so that ambient noise is merely reduced rather than totally occluded. (Also, unlike closed-back and especially noise-canceling headphones, they do not produce a constant pressure on your eardrums, which has been suggested to cause hearing loss and certainly plays a role in listening fatigue.) Their reproduction is quite good as well, with a surprisingly flat frequency response for the price range; if that suits you, you're good to go, and if you prefer otherwise, they won't interfere with you EQing your music to your heart's content.

Depending on where you find them, they run anywhere from $100 (Amazon Prime) to $180 (MSRP), so they're considerably less expensive than your QC15s, too. I really can't recommend them favorably enough.