I’ve been to T4 many times now. Best items are:
Passionfruit royal tea
Winter melon milk tea
Thai milk tea
Taro milk tea
Regular green milk tea
Now that the lines are less long at iTea, I have been back a few times. They have more variety, and I think they have an edge when it comes to fruit flavors, plus they have add-ins like sago and mango pieces. I think the boba is more consistently good at iTea, but T4 has perfect boba most of the time.
I’ve only been to Shiny Tea that one time, but should give it another try. The last time I tried to go it was closed, even though it was a weekend evening.
Incidentally, we went to try San Cha Bar (formely Chatime) and it was still pretty bad.
