UiiSii US90 probably has the same drivers that the HM6 and HM7 have, and even the build quality, nozzle diameter and tips are the same as HM7. The sound signature is basically the same, but the mid-bass is more boosted and the clarity in the mids and highs are not as good, for some reason.
If you're planning to buy these, I'd recommend going for the HM7 instead - they look more serious and sound a bit better.
Nice level of detail with a bright sound signature, and enough bass to keep things warm.
The build quality is simple, yet very nice.
These earphones smell amazing!
There is a bit of mid-bass bloat and some dirt in the mids.
There is basically no sub-bass, but I bet it's the intended sound signature.
The cable could be sturdier with a harder jacket and some proper strain reliefs.