The best Mexican restaurant I've been to in Phoenix.  Friendly and quick service. Delicious food.  Try the barbacoa tacos, they are incredible. The rice and beans are also excellent (good indicator of an authentic Mexican place).  I'd also recommend the lemonade as a solid addition.  As many other reviewers have noted, the carne asada is superb and better than anywhere else. Give it a shot and you'll be hooked.