I've only been to the Highland Park location, which I'd driven past many times and vowed to visit. The tacos are a dollar and are stuffed fullm which is great. I was surprised to find the ceviche (served unceremoniously with a large, fried corn ship with which to eat it) was delightful! Tangy and onionly and the fish was good. Yum! La Estrella rocks! And your will cost less than the amount of change in your couch!
Pros: Yummy, cheap tacos.
Cons: Don't go for the ambience. It's a stand with outside seating though there is a nice mural.