Just received my KBEAR KS2 today too. Standard shipping.
My wife saw it in the mail and she commented: "this looks like a toy, it looks very cheap." I didn't have high hopes until I connected it to my smartphone and I was pleasantly surprised by the sound!
The build is indeed plasticky and feels cheap, but don't judge a book by its cover, this set's sound quality is pretty good, considering the asking price of $20 - 30 USD. It looks for all intents and purposes like a cheap KZ, but the sound is pretty refined and a far cry from the typical KZ.
Build wise, it is quite comfortable, light, well fitting, above average isolation.
Accessories are pretty meh, a thin stock cable without chin clinch and some silicone tips, but nothing to fault at the asking price (in comparison, the TRN VX which cost $70 came with almost the same type of accessories LOL).
The KS2 sports a warm V shaped very well done, the upper mids/lower treble are boosted but not fatiguing like other CHIFI sawtooth upper mids. Subbass extends moderately well for a DD set, with good rumble and decay typical of DD sets. Bass is north of neutral but not at basshead levels. Bass is not particularly well textured.
Lower mids are recessed as typical of the V shaped tuning but not overly so. Treble is non fatiguing but extends moderately well, I like it, though maybe trebleheads wouldn't.
Technicalities are good for the price, with a wide soundstage, good imaging and details. Though for complex tracks sometimes the driver can't keep up in terms of speed, but nothing to fault for the price once again.
String timbre is okay considering it is a hybrid, but woodwinds and brass instruments sound like artificial toys sometimes.
All in all, a good all rounder for the price, I think it can suit most genres except maybe classical and jazz due to the timbre for acoustic instruments. This set would have cost way more if it was marketed under a western brand, I'm pleasantly surprised with it.
Will burn in more and compare it with other hybrids, but I think at this price bracket, the main competitor in terms of similar transducer type and graphs would be KBEAR's own KBEAR KB04 (yes it is very ironic that KBEAR would compete with itself in the same price bracket!).
EDIT:
Ok after spending a week with the KBEAR KS2, I'm afraid some flaws have come to the fore: basically the poor timbre and the overly V shaped tuning. It is okay in my book, but I think with the mega competition being released on a weekly basis, the KS2 might be forgotten in a few weeks' time. Final review here:
https://www.head-fi.org/showcase/kbear-ks2.24470/reviews#item-review-23922