Agree with u . . . "Costco 的还行 -- 总觉得欠了点什么" (same comment for their Chocolate Mousse Cake). Both cakes are GREAT for big party :p when u have many guests and don't want to spend too much $.
I have never tried Yuki Bakery 的 Green Tea Opera.
Normally we buy from (forgotten name, a very old and famous French pastry place ~NDG/Van Horne??), else http://www.degascogne.com.