Here are my early impressions of the SH-3 Universals after 3-4 days of ownership.
The SH-3 measures very much like a reference IEM. 2k, 4k and 8k peaks etc. The sound signature (in terms of FR) overall is slightly bass boosted. The perceived sound for me is neutral..Treble is slightly bright, but nowhere near ER4SR bright.
Compared to ER4SR, the timbre is more natural sounding. I find that it's FR is close to being colored whilst still remaining neutral. Note weight is heavier (which is better) but not overpowering. Due to the bass boost from 20Hz to 1000Hz, vocals are sweeter and and more life-like than the ER4SR which measures extremely flat from 20Hz to 1000Hz.
The main issue with the SH-3 from general opinion is that the bass is the only limiting factor. While the bass does not measure anywhere bassy, the quality of bass is lacking...common BA issue. The other issue is that the imaging is not very precise. You know where the sounds are coming from. You just cannot very accurately pinpoint the location. The sound is "bigger". To some extent it faces the same problem as the Legend X.
In terms of staging, this is where the SH-3 shines. Sounds are all very well separated and layered. Plenty of headroom too. It's incredibly easy to make out the location of the instruments and how far spaced they are away from each other in genres like rock and metal.
For the price I think it's very well performing. It doesn't have the sheer resolution the TOTLs have, but its resolution and detail is very respectable.
Overall a nice purchase considering I went in blind. I prefer it a lot over other reference monitors (Etys, inear PP8 etc).
Might consider a CIEM version down the line.