Picked up my ZS7, ZSA and some more cables at the PO today.
First things first ... thanks for the heads-ups on the ZS7 everyone!
My first impressions on the road w/o burn-in (Xiaomi Max2, Sonata USB DAC, flat braided KZ upgrade cable):
Bass, exceptional ...
fast & bone dry, hits like a brick if needed, not overboard anywhere but really well behaved on most of my test tracks (trusty Chesky recordings, EDM & some of my own acoustic and electronic stuff) w/ very little bleed upwards.
Mids: dry, crisp and beautifully detailed but the timbre of some acoustic instruments (strings, horns, piano, ..) is a bit off. I'll check the vocal department later.
Highs & treble: surprisingly all the extension I care for up there, great dry, crispy details (I like it that way) enough air and shimmer, decent rendering of cymbals, but here's the catch: my copies are as sibilant as a ¶|$$€d off sspitting cobra. At the moment I'm not too worried; if those critters keep sssissing after the usual 100+ hours on the burn in rig I'll take a closer look at the matter and fix it.
BTW, I don't remember who mentioned a 'dark' signature ; maybe KZ has changed something in the meantime but these are some of the brightest KZs I own (17 pairs).
Another plus in my book ... my copies sound just fine at my usual low listening levels.
Spatial impressions: surprising clarity and instrument separation; best of any of my KZs so far. Not quite as spacious, close to transparent or wide as the ZS6 but with more depth and perceived height. One more catch though: that 3d illusion, especially that of depth seems highly dependent on the frequency range; I've never seen or heard a 2 meter deep or long guitar before and will check into that issue with some other test tracks later. Anyway, I had a real good time listening to some 3d or 'holographically' enhanced electronic stuff through those IEMs but now it's back to some trusty recordings of acoustic instruments.
Bottom line: apart from the heavy sibilance mainly positive first impressions; can't wait to finish the burn-in phase and hear if and how that helped but so far it's been a pretty enjoyable fun ride.
Edit: image added