I finally received my pair after ordering a month ago and various delays. The numerous negative comments about being mid-fi and unflattering comparison to LCD2 nearly led me to cancel my order.
I have been using the HE-6 nearly exclusively for the past two years despite trying all other flagships.
All I will say is that I am really surprised by all the negative comments as it is a superb headphone. I only detected a slight tonal unbalance so far in the upper mids but imaging, treble and detail retrieval are all first class and very close to the HE-6. The mids are more pronounced, smoother and more detailed than the HE-6.
The Hifiman is more open and spacious and has better timbre.
My main disappointment is with comfort. The pads are small and my ears get quite warm quickly. I slightly prefer the roomy feeling of the Hifiman pads (Beyer DT990 pads in fact) so far.