The K267s sounded great out of the box - I had no expectations as with the M-100s and tI didn't follow the hypetrain until their release, I simply read an article and bought a pair to try as I couldn't see any reviews anywhere.
So, after comparing them both these are my initial thought and bear in mind, the M-100s have had about 20 hours on them and the AKG prob 3 hours.
Build quality:
While the K267s are built well, there really is no contest here, the M-100s just feel sturdier, the finishing is more refined like an apple product, no flaws that I can see. K267s aren't bad, they're actually very good, they're just not on the same level as the V-modas. The bass control on the K267s feel a little plasticky which I don't like but they don't feel like they will break anytime soon though.
Design:
Subjective I guess, everyone has their own tastes in design, however the sleeker feel of the M-100s means they would be easier to wear out. If you took both headphones back to the 80s, no one would bat an eyelid at the AKGs (but the men in black may pay you a visit as the V-Modas look like they're from another planet.). They aren't a very attractive pair of headphones it has to be said, in fact I really don't like the design much. M-100s on the other hand look fantastic to me, esp in matte black and the little things like angled jack, kevlar cable, etc. are nice. They also fold down really small which helps with portability. AKG realyl should have given you a hard case with the RRP on these.
Comfort:
K267s pads are nice and slightly thicker and the cushioned headband is nice as well. I wasn't one of the ones who found the M-100s particularly uncomfortable but the AKGs are noticeably more comfy. As you can see the eurcups are different, the AKGs are circular and were more comfy.
Sound:
After trying out the M50s, HD25s, MDR-1R, UE6000 and Momentum among others against the M-100s, I felt while they were all good in their own ways, they never really stood on the same level as the V-Modas. The AKG K267s are probably the only one of the new batch that in my opinion stands up as a worthy rival to the M-100s.
I really enjoy the sound from the K267s, they are almost like an M50 with a bit more oomph I would say, better bass definitely, quality and quantity. I left them on the club bass setting.
Female vocals sound a tad cleaner and clearer on the M-100s, male vocals sound better on the K267s. Luthor Vandross "dance with my father" felt more engaging on the K267 for example, and just didn't sound right when playing it on the M-100s. I would say the K267s are ever so slightly warmer in sound, they have better mids and that's what I noticed straight away when comparing. However, there is such a nice clarity to both headphones it has to be said. The bass on the M-100s is tighter and cleaner whereas it sounds like there is more bass boom on the K267s (not in a bad way). Both do the bass very well, but in a different manner. I tried Madonna's "die another day" and both performed well, there was a tad more clarity with the M-100s, you could hear the hand claps and violins more distinctively at the start but the warmth of the sound on the K267s and the bass slam went hand in hand with the track I felt.
I am aware it's an unfair comparison until the K267s have had time to burn in and what not but these are my initial thoughts.