Got the HEK in today, spent a few hours with them. Not bad at all. Somewhat unique presentation to my stalwart HD800s -- I feel I get a long more string noise, pedal squeak, valve thunk, etc. Same amount of music, just more of all the little ancillary bits, which surprises me.
My main setup has always operated on the "high end thunderdome" principle, whereby you can only keep your favorite, and all comparison only serves the purpose of figuring out what to get rid of. I didn't buy these, and I have to eventually return them to Fang, so it's a treat to be able to listen comfortably in my own rig knowing that I don't have to decide whether I like them better than anything else. They make my ears real hot, though.