I received my HE-5 yesterday and have several hours on them. Note, these are initial impressions only, and the HE-5's are SE, my hd800's are balanced w/ a custom cable. I am using my pc/foobar/weiss/badac source and switching amps b/n my B22 and the EF1(also received yesterday). First impression, I am very, very impressed. The level of detail approaches, but does not quite reach hd800 level, no matter which amp is driving. Bass is more full and deeper when using B22. Upper octave range and detail extended when using B22. However, the EF1+HE-5 combo for the money is a ridiculous value. The differences, though not entirely subtle, only emphasize what a resolving set of headphones these are. In two aspects, they are more easy-going than the hd800 as they are not nearly as component sensitive and do not accentuate pre-existing sibilance as the Senn's do. Which is better? I'll definitely need more time. But the fact that there is such a close comparison speaks volumes for this can. Comfort-wise, I prefer the larger diameter of the hd800. The cups on the EF-5 are on the verge of being slightly too small. Fang, congrats on a top-notch product and an incredible value. Any chance of your offering a balanced cable? I would love to put these cans head to head against the balanced hd800's.