We went to Dok Bua last night around 6:30. It was almost completely empty--perhaps because it's school vacation week.
While my soup was disappointing (clear soup with tofu and vegetables; it has a sticky-sweet fish taste, which was rather unpleasant to me), the vermicelli with crispy chicken, chili sauce, and basil was outstanding. It was very hot, but not excessively so, and the vermicelli was about the best I've had anywhere in Boston.
Can't wait for my next trip back there, though I do want to get back to nearby Khao Sarn and House of Siam in the South End at some point.