Barrio is the best! We always bring out of town guests here for dinner. We had one guest who was here for four nights and two of which we had barrio! The prices can't be beat, and the tacos are amazing. You build your own, and can add one rice, avocado or another protein for $1. Try their chef specials, too. My only complaint is that the margaritas are always weak, so I've stopped ordering them. The place is very casual, and always busy, except the wait time is never too bad. They will tell you how many tables are in front of you, not a time estimate usually, but tables rotate pretty quickly so it's not usually too bad!
Update: I went again on a Friday night and ordered margarita pitchers from the bar, and they were perfect! I could definitely taste the alcohol in them. Not sure if it made a difference because I was standing there watching them make the pitchers, but I was very happy with them. The bartender measured all the ingredients he put in, so hoping for the same consistency next time we go!