I really like this headphone for a number of reasons. First, the sound stage, I've never liked listening through headphones; because. of the inaccurate spatial presentation rendered by most headphones I've owned over the years. The AKG K 550 deliver a listening experience more like loudspeakers in this regard. I don't hear or perceive the musical instruments and voicals as points of sound in my head. The sound stage is eapansive and has a three dimensional quality to it. It's the most natural sounding headphone I've ever heard in this regard. Second, the overall sound, frequency response, dynamics or musicality, I'd just say very accurate. I've used them with my Audioengine D1, Onkyo C7030, and Onkyo TX 8050 headphone amps, and they deiver a listening experience as good and somewhat better in certain ways than my JBL L890's. Also, I just want to mention, their bass response is excellent. Beats, they're not. Audiophile, they are. Third, fit, they're really big, and despite their size, they're really comforatble. I wear glasses, and put the 550's on all the time and don't feel the need to remove my eyeglasses. While the fit seems a little loose, they stay on just fine and seal well, but they're not suited for use at the gym.
Pros: ten foot cord, screw on one quarter inch adapter, very musical, very comfortable, excelent value
Cons: AKG should offer a storage or carrying case, either as part of the origonal package or an after market accessory.