All of the above, but it is a comfortable CLOSED headphone. If you need or want a closed headphone for isolation, the field narrows quickly. Most of the "reference level" headphones are open designs. There are other closed reference level headphones out there. From what I've heard, (not that much at the high end, the old Denon D7000, the Fostex T900, the Audeze LCD-XC, the JVC high end can that may now be discontinued) none compete on a $ for $ basis. The LCD-XC is a pretty great sounding headphone. It is way pricy, and for me feels like something from the Spanish Inquisition torture chamber (ok, not THAT bad, but heavy and uncomfortable). The Denon's and Fostex sound great, leak like sieves. That JVC (D1000 maybe?) felt and sounded like I had my ear to a 5" diameter pipe, just kind of claustrophobic. The Primes? For me, none of the issues of the other closed cans. Comparing to open cans, the competition gets a bit tougher as far as airiness and sound stage goes. For me, the Primes still ultimately win, because there is always a fan, wife, daughter, dog, cat, something making noise while I try to listen. My Oppo PM-1's spend more time in the drawer, because of this. I haven't sold a kidney and bought an LCD-X or 3 because of this. I don't own HD-800's because of - oh, wait, it's because I don't like the HD-800. They're like driving icicles into my ears......
Fanboy disclaimer - I like Mr. Speakers. I like Dan's voicing. I like Dan. Still, the Primes are awesome, but do consider the disclaimer.