While their locations seem to work for a lot of people and I love the idea of quick & cheap taco, I have to agree with other reviewers who simply can't believe Taco Shack gets away with operating in Austin. It's all about the food.
Although I hear the standard PEB (potato, egg, bacon) taco is good when the eggs are fully cooked and seasoned (yes, please!) I've never tasted anything in a tortilla as bad as their barbacoa. My taco was apparently not warm enough because, upon first bite, I encountered hard chunks of fat mixed with a greasy, bland excuse for beef. Nothing mouth-watering here. The fat was easily visible when I flipped open the taco and my appetite flew the coop. Didn't even take a second bite.
While my El Nino taco was OK (I've had better chorizo from HEB,) the Bevo Burrito failed to deliver. The fajita steak strips were stringy and tough, and should have been better seasoned. I expect to be able to chew a normal-sized bite each time but had to really work at the beef. That taco just didn't taste right.
Previously, I'd also ordered the beef enchiladas -- might as well call that enchilada ""pie."" Mine was a greasy, unimpressive to-go order.
It's sad to say but any number of chain restaurants can consistently beat Taco Shack. They've got a good idea but really need to step up to the ""plate.""
If all you ever long for is potato and egg, you may be satisfied. I grew up in San Antonio and I know good Mexican food. This is not it.