I have hesitated responding to this thread because I have been a bit lost in Wuyi Oolong vendors myself lately.
Mandarins Tea Room has some stellar products, but you definitely pay for that quality.
Besides that I have looked at Hou De, Red Blossom, and Jing Tea Shop. Of which I have had varying successes and failures. Hou de has stuff heavily roasted but they seem to sell it far to soon, so unless you want to buy yancha and sit on it for 6 months if not an entire year, it will likely seem harsh. Red Blossom is nice, but slightly underwhelming. While Jing Tea Shop I feel you need to really pay for quality, and even then its a bit of a gamble. Jing Tea Shops budget stuff tastes just like it sounds, a budget offering, while their higher end stuff is hit or miss.
I want to try more places, but I have a hard time keeping up with orders for what teas I want to drink/ am drinking.