Some Burros is inexpensive, and that's the best part. The burritos are so-so, the lettuce is a bit suspicious. The refried beans have very little flavor.
The decor is no more than a usual cheap Mexican food joint. It's not trying to be flashy. The eating area is filled with metal chairs and crooked tables. It's usually loud and not very clean.
To maximize your experience get the shredded beef with green chili sauce. Remember: you aren't going to get "fine dining", but you'll probably leave full.