I ate here almost every day for a week while staying in Queretaro. The food was consistently tasty and quite inexpensive. There is a menu of the day with a filling meal of vegetarian food under 4 dollars. There are also a number of regular items that can be ordered from the menu. I especially liked the burritos and Huevos Mexicanos. Service was quick and the people who run the place are really nice and friendly. Note that they stop serving lunch after 2:00.
Cons: Limited hours