Phat Burrito is an awesome burrito joint on the Camden Road hipster corridor of South End. Definitely try the burritos and quesadillas. I typically get a chicken burrito, which is packed with shredded chicken, black beans, rice, guac and sour cream.
The food is cheap and filling. As for all the reviews that claim this isn't authentic mexican...duh. Phat Burrito never claimed to be authentic Mexican food. If you're looking for real Mexican food, head east on Central Avenue to La Unica or Casa de Las Enchiladas.