Well I certainly like my 701's out of a Headamp GS-X. I agree that amps make a difference, but to me the biggest improvement comes from doing a dual entry recable (I don't even care what cable you use ... Oh no heresy ). I think the engineering genius who thought up the single entry system on the 701 should be forced to listen to a stock 701 out of an ipod shuffle until their internal auditory meatus falls into the nether regions of their arsehole. After the dual entry recable, balancing helps to deliver more power which certainly helps. Of course that raises the real price of the K701 to a somewhat higher level . Almost everyone at the Chicago meets have been favorably impressed with the balanced 701's out of the GS-X, including a few who sold their stock 701's because they couldn't stand them. I guess it's not really rocket science, do what you can to get a clean, powerful signal to those drivers.
Oh and I think headphone burn-in is partially the drivers burning in as well as the owner acclimating to the sound. Sometimes the acclimation never comes (Can you say U-l-t-r-a-s-o-n-e? I thought you could, but that is another thread entirely )