I've just come back from the demo session too. I listened to it for nearly 45 mins in complete silence and had my T1's and Ultrasone Sig Pro's at hand for comparisons sake.
Basically guys, Nomax is right.
Seriously, strap on tight as AKG have released a monster of a headphone. A real real beauty. I almost cried when listening to it.
The real judge of how good this headphone is will ultimately come when you get the chance to listen for yourself, but it's better than the T1's and better than the HD800 in my opinion. I have very rarely, if at all, described a headphones sound as beautiful but this is what this is. It's so clean, clear, resolving, weightly, full, dynamic, layered and above all natural. No artificial brightness, sibilance or peaks. Bass isn't light or under-energised. It's closer to the Sig Pro's in weight and quantity rather than the T1's. The soundstage is HD800 style wide. Definitely wider than the T1's.
What really Impressed me. No that's a lie. What really scared me was how good it sounded out of my SGS I9000 smart phone (Voodoo sound). Wow. I can't see driveability being a problem with this headphone.
I agree with Ra97oR about the cable in that it could be more flashy/impressive but it's completely functional and I'm someone who likes thinner more easier to manage cables rather than the T1 type. Something like the Ultrasone Signature pro's cable is the best - could have done something like this. He explained about how this can be driven from an ipad for use when musicians mix/take ideas down on it (that's true) and when one considers that, the cable makes more sense. Overall build apart from that is very good.....
....might as well just write a review on listening impressions, rather than just type whatever I'm thinking. I'll be back shortly..
Edited by CantScareMe - 10/10/13 at 1:42pm