I tried this cart for lunch on Library Mall and wish I could have gone back for more! I ordered one pulled pork bun with edamame for $4 and was happily surprised by the large pile of edamame, but wish I had gotten another bun. I definitely recommend getting the 2 buns + side for $7 if you are looking for a full meal.
The buns of the little sandwiches are "mantou" buns (aka steamed buns) and are a wonderful pillowy delicious goodness - I'll definitely have to go back one of these days.