So incredibly disappointing! As a vegetarian the Vietnamese sub is always appealing. Unfortunately the vegetarian banh mi I had was by far the worst I've ever had, specifically the tofu wasn't cooked or flavoured and the bun was terrible. Maybe a one off by my friend ordered the chicken sub which she said was "eatable" but not something she would pay for. The vermicelli noddle soup was ok but somewhat light on the vegetables and flavour - fine if you are in a pinch.
I think we have some great Vietnamese restaurants, OPTO adds nothing to the 4th st food scene as a gourmet bistro or as a fast food option.
For the positive - it is a clean, bright space and the food is fairly priced. Although I would not pay anything for vegetarian sub.