It's a 2013 model, actually. First impressions, on comparing this to the Grado SR-125 the AKG's are replacing: It was readily apparent that the AKG's had an airier, sort of more crystalline sound. It took me several listens to pinpoint what it was I was really hearing: More high frequency, maybe, but also with (and I don't use the word lightly) a breathtakingly more vivid soundstage -- by which I mean that all the instruments are much more precisely located in space than with the Grados (which come off sounding kind of warm in contrast, the mix more blended). You can really locate instruments and musical parts. I've always been quite satisfied with the Grados (which I'll keep for computer use), but I have to say, I'm surprised by the striking extent of difference.

One often reads that these headphones require an unusually long "break-in" period; I'm reflexively suspicious of such claims, but perhaps (who knows?) I really will come to see that in time the AKG's become less bright sounding. That's quite distinct, though, from the matter of the precise soundstage, which I'm sure I'm going to like in these for all time.

One also reads that these require special amplification, but I'm not so sure. I'm playing them through the headphone output of a Marantz SA8004, and while I do find that I have the volume control dialed at something more like 3 or even 4 o'clock (as compared to the 11 o'clock setting the Grados require for the same music), the Marantz's built-in current buffer headphone amp seems to do just fine -- it gets the phones to 85 dB (measured) without running out of gas (as evident in the non-fatiguing character of the sound; they AKG's are playing plenty loud with no onset of distortion).

Bass: jury's still out on the widely-seen comment that these aren't as impressive in bass. You do have to play them pretty loud (again, pushing 85dB) for it to be really satisfying (which by that point it is) -- but you can comfortably do that with these because they remain so non-fatiguing, so clear and orally comfortable.

And speaking of comfort: Preliminary impression is that they're every bit as comfortable as the light-weight Grados -- though again, perhaps, in a less-fatiguing way.