what is your preferences? do you like bass impact? or bass light? that will be a question for AS16 and AS12 and A10, if you want bass impact, and less bright, skip those. They are more on bright side, less bass impact, and can be tiring on highs. ZS10 pro were the fave of the month, few months back until they have a better ZS10 Pro which is ZSX, more smooth trebles without infamous metallic sounding of ZS10 Pro. C12 is ZSX sibling, they are almost same and the newest from company to date, while ZSX more balance, C12 a bit aggressive on upper mids and lower highs region. your best bet from KZ/CCA are ZSX or C12, they are better than previous KZ in many aspects (KZ and CCA getting better in every product they release, but just gradually, slow improvement until they reach decent ZSX and C12) yes but ZS10 pro have metallic sound, and they fixed it with ZSX, ZSX is a revision of ZS10 Pro, with no harsh lower treble. Can you describe more about impact? ZSX isn't thin sounding, they have decent weight on notes, but if youre talking about fun impact, they are more balance and not too impactful on bass . on other side V90 is very impactful on Bass slam and punch, but slightly recessed mids area, more v shaped than ZSX overall. Both are nice IEM for $50 category.