I still think the ZS6 was the best deal of 2017 for IEMs. Something to consider when the sub-$50 Knowledge Zenith ZS6 did well in comparisons with the likes of a $400 Westone UM30 and a $400 Noble Audio Trident, though it's all subjective.
It's food for thought but I don't mind saying the ZS6(i) is a great IEM, especially at under $50.
We stone UM30
Noble Audio Trident
KZ ZS6
Definitely something worth to try. I love how the ZS6 sounds with my Pioneer XDP-100r but with SU1 > Holo Spring level 3 > ECP DSHA-0 > ZS6, it is on a different level. A straight WOW came out from my mouth when the music plays albeit a quite overkill setup for ZS6.