I don't typically care for authentic Mexican food.... BUT!
There's a newer restaurant off of S. Broadway. The name escapes me. It's behind the hotel there and the Waffle-House.
The food was fantastic... We went right after they opened, and I guess were possibly short staffed? It just seemed hectic in the front of the house. I'd recommend maybe taking a Spanish speaking friend. (Had it not been for my boyfriend who knows how to speak Spanish, everything would have came out horribly wrong.... and I know this... because he wasn't there when we ordered dessert... Hehe.
)