For whatever I can contribute from my limited listening experience, top of the line universal IEMs such as the SE530s, Triple Fi 10s, ER4s, without equalization sound like CHEAP TOYS compared to customs like JH16 Pro. And it really all comes down to passive crossover tuning.
If you equalize you can still save the farm, but let me tell you that being pulling out this kind of clarity and dynamic range throughout the entire frequency spectrum without touching the equalizer, is a feature that no universal IEM I've heard until now has achieved.
I was extremely satisfied with my equalized SE530s, and once I put on the JH16s I almost had a weird feeling like "this sounds different, but I'm not sure it's better different", because I was so used the SE530s that my ears took that as the "reference". Then after a week of listening, I tried the SE530s again. I laughed, took them off, and unplugged them after 30 seconds.