This place is (usually) great.
They've recently updated their Happy Hour menus and removed their late-night happy hour option. Now it's 3-7 M-F and weekends 2-6. Not bad overall, but I used to LOVE coming here for late-night happy hour.
The happy hour food specials aren't too amazing. Everything is still between $6 - $8. The best deal is their $5 Chambord Margarita. It packs a serious punch and is incredibly tasty. I'd say come here for that, and that alone.
Service is usually great, the food is usually pretty good, and when it's nice out, the patio is amazing. My wife's favorite food item is the Street Tacos. I love the Tejas Trio, but don't really like their Quesadilla, Nachos, or Tortilla Soup too much.
I would recommend Z'Tejas for Happy Hour, but not really as a regular Lunch/Dinner place unfortunately.