It would be nice if there were non-electrostatic headphones that were as good as or better than the Stax SR-007. It's kind of boring that the SR-007 have been better than anything in production for quite a few years now. When the Stax C32 is introduced, the gap will probably be even wider, with even less of a chance for non-electrostatics to catch up.
The only reason I see for going with any full-size open headphones other than the SR-007 (or C32) is cost. However, if you buy HD800, T1, HE-6, ED10, etc. with a high-end amp (Beta 22, GS-X, Apache, B-52, etc.), you come pretty close to the price of the SR-007+KGSS. Also, many people buy multiple dynamic headphones and amps because something is always not quite right with any given setup. My advice is to just get the SR-007/KGSS and be done with it. You can then just focus on the music rather than the equipment, and your wallet will thank you in the long run as well - less equipment churn.
People buying Apache or B-52 are just plain rich. They probably have an O2 system or don't bother to have.
A self-built b22 can get you way less than 1K$ in cost. Add another say 400$ to commission a head-fier and you're really close to >1K$.
O2 + KGSS = 4800$
b22 + hd800 = 2500$ ~
So it's not really close.
A dynamic system will always be budget-constrained one even in these numbers.