Opera Max is available in Vietnam, but it is blocked on Phu Quoc, a small special economic zone island.
I am trying to access this site http://www.phuquocislandguide.com but it's not working. It works in Ho Chi Minh City, Danang, Da lat, Hanoi, and Nha Trang.
However, the underwater internet cable has been cut so that may be the root cause of the problem. The cable is supposed to be fixed by the May 17th so i will double check again.