If you like the HD800 more than the HE-6 (which you don't), you will like the SR009 as it resolves spatial nuances and sonic textures in a very realistic manner and has more soundstage depth than any other headphone I've tried. It is extremely quick in the transients, rendering music with feather-like agility. It has more body to spatial cues than the HD800. It has deeper bass than the HD800 and probably the HE-6 (by a hair).
That being said, it has this "ethereal" quality due to its feather light nature which is certainly not for everyone. Some call it a "colouration". If you like the HE-6 more than the HD800 (which you do), just let me say this: the SR009 is less tactile than the HE-6, has less soundstage than the HD800, is much more expensive to buy and amp properly. The SR009 will not hit as hard or impactful as the HD800 or the HE-6, even the deepest bass notes hit with a slight "fluff" in the sense that they hit and run and there is little sustain.