Lets start with sound
Its has 3BA per ear, its accurate, fast, tight, clear
Reviews are done on just my pixel 2 with no EQ tinkering
Bass: Accurate, too accurate in fact, it doesn't decay like a dynamic driver would, does not hit as hard a dynamic driver would. No bleeding.
Mids: Clear and accurate, if i have any complaint, it would be sometimes vocal sounds like their singing amongst the instruments instead of in front. But this is probably a physical limitation of IEM since i am comparing it to an HD25-1 ii.
Highs: Inoffensive, non fatiguing, one of the biggest plus since i bought this for travel and extended listening.
Soundstage is small and intimate, potentially making vocal sound drowned out by the instruments if not the the excellent separation and imaging. You can pick out the instrument sound and direction easily.
Comfort is amazing, i can wear it all day. Most times after buying the bluetooth cable for it, i just wear it without listening to anything, since i appreciate the silence. Stock cable are light enough that it doesn't irritate the sensitive part back of my ears. The silicone tips are great too.
Build quality is MEH
The shell opened up not long after i bought it, fixed it with glue at the slot-in points. Luckily it happened at home. was not a big deal.
The two stock cable broke, the braided cable just popped while i was sitting in front of the PC, the smooth cable got really loose and barely hold its shape above the ear. Bought myself a better cable and a bluetooth cable to fix it.
Also, the 2-pin connector can get a bit loose, the upgrade cable i bought for it didnt have parallel pins but it made the connection tighter, it turned out alright. Not recommended way to fix this it to slightly pinch the the two pins together, but i wouldn't know how one would do this with the shrouded stock cable
Spin-fit CP800 really helped with sound quality, it gave it more space and also better comfort.
if you're into foam, Comply T-100 is what you want.
For cable upgrade, you'd need the standard 2-pin 0.78mm connector cable, TRN BT10 is amazing on it, i've been using it when i jog, when i cook, washing my car, you get what i mean, the bluetooth cable brought this IEM to a whole new level since both the IEM and BT10 cable are super light.