if you go -- and you REALLY should if you love Mexican food, know that this is hole-in-the-wall type of place. Your pants kind of stick to the old booth seats; the lighting is dim; the smell is a bit funky. BUT the food is awesome! And the service is friendly.
We had the chile rellenos and the huevos rancheros, and both dishes were very authentic. In fact, I'd have to say it was the best relleno I've had in Colorado.
Be aware, though, that they're not fooling around about the sauce. Medium hot REALLY is medium hot; I'm guessing the hot hot would bring proper salsa tears to you eyes.