I probably would have passed Pho's Thai by were it not for the "vegetarians welcome" subtitle below their sign. This is a small, quaint restaurant with simple dishes that feel home-cooked and authentic. The "garlic oyster sauce" they use is, in fact, vegan and they also have vegan curry stocks, which is rare in American Thai restaurants (they usually have either shrimp paste or fish sauce pre-mixed in the curry sauces).
I had a pad prik lunch special ($7.20 with tax) and chose "imitation meat" over tofu. The dish also came with a light vegetable soup and a fried spring roll. All in all it was a great value and the dish itself was tasty and basic, like a home-cooked stir-fry. I only wish they had brown rice as an option.
(For the record, the imitation meat is denser and chewier than tofu though it looks similar.)
The service was friendly and welcoming. I would definitely come here again to try their curries and other stir-frys. It's rare to find a Thai restaurant so accommodating to vegans and I think this is the one for Chicago.