There is something on that as well, but also the term "quality" is not that standardized like with coffee ( More attributes involved ), so it's more complex to define which vendor has a better quality . Also big seller can not source some unique / rare teas because that is more time consuming and not that profitable ( yet some big vendors claim they do ...just marketing ) , unless being simultaneously on few mountains during the actual harvesting and supervising tea leafs on the journey from the tree to the box. Hiring people for doing so , is costly. Saying we have a trustworthy farmers we cooperate with....ehmm, well, suit your self with believing this one

Those who do Tbiz here in China and know, just laugh. Those who don't and believe, just pay

Agree with Bok, buy samples and compare.
And hey guys, we have a Mei Leaf Chat back again ! The same one as on steepster

Can't wait the guy with posting how many followers their YT channel has;-D
( https://steepster.com/discuss/22030-mei-leaf-chat )