Not my favorite place to eat if I want simple food. If I'm going for a taco plate, I much prefer Rolando's Super Tacos. If you're looking for fast food mexican with a much more authentic flavor than Taco Bell, there's always Pollo Loco (or Taco Cabana if you want really fast food). If you want tamales, Ruben's Tamales or Delicious Tamales are local favorites (though personally I prefer Ruben's over Delicious). If you want local color (and don't mind cost), Las Margaritas downtown is terrific.
With this being Fiesta time and all (think southwestern Mardi Gras), its a great time to just tour the flavors.