This is the perfect (big) hole-in-the-wall for a snack/lunch after or before the market rush.
No fuss. No flare. Just tacos and things. They also have a grocery section that you can pick up tortillas, guac, queso, etc.
Although I've tasted other things there I always end up taking the menudo soup (tripes) and the lengua tacos (beef tongue) and they are always delicious.
Honestly, just go.