I tried the 12:00 to 14:00 lunch buffet here, which I found pretty good. The buffet seems to be popular among locals, so consider making a reservation or you have to eat in a big table with others. Some of the dishes have dairy but it's relatively easy to spot. Ask the staff if you're unsure - Mandarin skills help.
The only problem with the restaurant was that the restaurant hall in the basement floor smelled strongly of cat urine.
Cons: not vegan, smelly