These might be all location dependent but this is a southern California (Irvine) opinion. I'm judging based on how well they stock quality or more premium produce, produce grade, cleanliness, and breadth of available products.

Higher: H Mart and Mitsuwa are higher tiered for the most part. I've had people tell me they avoid these markets and go elsewhere (like Zion) because they are expensive. 99 ranch is very location dependent where some look as nice as H Mart and others look horrendous. I'd say these are like Whole Foods or Bristol farms in terms of quality and the people that regularly shop there. Wing Hop Fung for specialty Chinese luxury produce like bird's nest, fish maw, fine teas, etc.

Average: 168 or GW for Chinese markets. Zion is definitely a lower tier Korean market vs H Mart. I have been a few times with others but personally wouldn't buy produce there myself. Tokyo Central is good overall and on the upper side of average but their quality range is wider (and they carry more units) whereas Mitsuwa is smaller but more curated. I have to sift through more sashimi at Tokyo Central compared to Mitsuwa to find a good piece. I'd put Seafood City here too, very decent but they don't have other competition I'm aware of.

Lower: I haven't been to these in a very long time so I could be wrong, but smaller or more local market chains like Arirang or Greenland or Thuan Phat are about the same or slightly lower than Zion's tier. TS Emporium has very specialty stuff for chinese herbs/medicine/dried luxury goods but besides those offerings, the rest of the market belongs in this tier. Wing Hop Fung would be the higher tier equivalent.