Got it in today, earlier than I expected, and have been listening to it for awhile. I have to say, this thing is the real deal. It's been exceeding my expectations, so far. My thoughts so far really mirror DarKu's review.
It's a noticeable step up from both the iCan SE and the Massdrop CTH to me. Everything sounds super effortless, as if a certain listening tension has been relieved. Some might interpret that as being a bit laid back, but I don't find it overly so. I liken it to a similar authoritative effortlessness I heard with the HE-1000 loaner a while back, except that I'm using the HD-650. Like other's have alluded to, it manages to pull off the rare feat of being both very detailed, yet non-fatiguing, given the aforementioned effortless nature. It does seem to have a slight warmth to the sound. If I had to nitpick, this can be slightly strong with the HD-650's already strong midbass. However, the extension into the low bass helps keep the overall signature still well-balanced. Synergy seems excellent overall between the GLite mk2, Qutest, and HD-650. I'm feeling content with my front end for now, I think. Next upgrade, when finances permit, will be more/other headphones.
I haven't yet tried the Elear with it, though I intend to. I'm planning on selling the Elear to offset this purchase, but I want to see how it sounds in the new setup, in case I want to go for the Clear in the future.
And a special thanks to Justin for taking some time out of building GS-X's and BHSE's to throw a bone to us mere mortals
I suspect this may end up a classic once out of production.