Well, that was an almost comically fast failure! Sound on the right side cut out. Swapping sides on the cable didn’t help and continuity test shows that the cable is carrying a signal on the shared ground and on both sides, so I guess it’s the driver that’s bad. Return to sender 
From the brief time that I had listening, my impressions would be as follows:
Comfort
These are pretty light for a planar magnetic, and with the nice suspension headband they don’t cause any hotspots. The clamp however is pretty unreal - stronger than any of my other headphones, and exacerbated by the extra thickness of the ZMF Ori pads. Given the headband shape, it’s not clear to me how I would fix the clamp like I did on the HD58X.
Burn In
I did let the headphones burn in overnight and didn’t hear any noticeable changes this morning.
Sound (with ZMF Ori Pads)
Definitely on the bright side, though nothing like the DT 1990 I used to own, and it’s fairly smooth and well balanced. The rendition of metal percussion like cymbals and hi hats may be the most realistic of any headphone that I’ve heard. Most of the midrange is pretty neutral sounding, though the upper midrange is perhaps a tad hot. Bass is well extended but sadly a bit anemic, even after EQ. I tried some music with solid bass content like Alicia Keys’ Songs in A Minor, Daft Punk’s Random Access Memories and Charles Mingus’ Haitian Fight Song. Perhaps I’m not giving it enough juice, but the Ember II is capable of putting nearly 2 watts into the HE-560, so I’m not sure that it’s starved for power.
Timbre for most stuff, including piano, guitar and voice, sounded strikingly good. I remember the HE-400i having a slightly whispy kind of timbre, I hear no such issue here.
Clarity and detail seem fine, though not necessarily outstanding. Part of that may be that the slightly brighter sound signature keeps me from turning up the volume as much as I would with the LCD2C, so I’m not getting into the sweet-spot in terms of distortion and clarity. I recall having a similar challenge with the Focal Elex.
Soundstage and imaging seem okay, though I didn’t find it particularly immersive.
Bottom Line
Overall, the HE-560 sounds very competent, but unlike a lot of other headphones I’ve tried it doesn’t have any clear standout characteristics that really grab you on first listen. From my admittedly limited listening experience, true TOTL headphones all have at least one standout characteristic (often accompanied by at least one glaring flaw). The HE-560 does not fit this mold. If it would actually keep functioning for more than a day, it does seem like it could be a decent all-rounder.