I have now been to los picos 4 times, always in the afternoon and never have I been disappointed with the food or service. Yes the food can take awhile but this is not Chipotle, the food is made just for you and the cocktails are fantastic, especially the house sangria.
Obviously because it is west mesa its not the greatest of locations but good authentic mexican food is not easily obtained in the Phoenix area. Ironic, I know.
I highly recommend the mole chicken and the carne asada dinner.