Great barbacoa and gorditas; be prepared to wait a little.
I've spent a lot of time eating out of pushcarts and pickup beds between Monterrey, Matamoros and Reynosa, and this is my favorite little taqueria in the Metroplex so far. El Tacaso makes their own gorditas, and the simple bean and cheese version is surprisingly flavorful. Many purists may reject the "barbacoa" that is not barbacoa de cachete, but El Tacaso's barbacoa is too good to pass up, especially when served all the way with onion, cilantro, and lime. At other restaurants I usually prefer the less-bitter green sauce, but El Tacaso's red sauce is just as satisfying. They also serve good chorizo, tongue, tripe, and fajita tacos, but they don't stand out quite as much as the barbacoa and gorditas. The prices aren't particularly cheap, but they're not outrageous given the quality of the food. The only real downside is that you usually can't just run in and run out; it's authentic all the way, even down to the pace of service! Good place to get takeout when you're in West Dallas, and a good place to sit down and eat if there are only 3 or 4 people in your party and it's not very busy.