So I bit the bullet and ordered these. They finally arrived, so it's time for first impressions:

Build impressions:
The finish on the cups is very nice, the headband feels sturdy enough, but alas, I can't shake the impression that some parts look kinda fragile for a 250 USD portable product. So, a carrying case is due, thankfully they fold into a very manageable size. They are light, but not toy-like, the cups have a nice heft to them.

Comfort:
Very comfortable, very soft and spongy pleather pads that can get slightly sweaty after a while. They can be worn around the neck without issue. I don't think many people will have clamp issues with these, either.

Isolation:
Above average for portables, I guess. Should be enough for most uses.

Sound:
Keep in mind that neither I or these have 'burned-in'. I have about 4 hours on them total played straight from a Sansa Clip+.

Bass:
Bass is very extended and moderately emphasized from ~120 Hz down, nice weight and texture to it, not muddy, feels close to 'big boy' bass. The hump can become slightly problematic (boomy) with some music, I found that a 3 dB reduction around 110 Hz did the trick. I'm also under the impression this could be improved with further damping on the earpad side (jergpad-like holes or velour pads), driver seems to want to displace a lot of air that is just trapped in there.

Mids:
Mids are flat, not cuppy or colored in an obvious way. Slightly distant upper mids, but less so than the M40x, this helps with bright recordings. Nice resolution, able to dig more into the mix than at least the M40x straight from the Clip+.

Highs:
Highs are nicely extended and present, but not very forward or artificial sounding like those on the M40x. No sibilance-inducing peaks so far, though bad recordings can come close to being annoying.

Imaging:
Hit-and-miss so far, some stuff has pinpoint imaging while some other sounds slightly blurred.

Dynamics:
Even with the dynamically-impaired Clip+ these are reasonably punchy and believable.

Presentation:
This was the main reason I could not live with the M40x, I found their presentation annoying, the uber-hyped upper highs were detached-sounding even after modding and EQ, the soundstage was weirldy squashed and not very coherent sounding, and the perceived depth was affected due to the 4 KHz dip. These sound much more coherent to me, soundstage is not big but it's nicely rounded with perceivable height and depth and some sense of space, I guess amplification could yield improvements here. Also, surprisingly 'big' sounding for their size, the PortaPro and Momentum On-ear sound 'smaller' in comparison. Overall very smooth sounding.