The best I can say for "Los Aztecas" is that they found a way to make mexican food appealing to the "midwest palate". *it is not* authentic mexcan food!!! (yes, the names are authentic, but again, they have been "americanized"). In the Dubuque Area, if you want *authentic* mexican food, go to "Las Margaritas" (In JFK), or go have some tacos to "El Paisano" (the mexican market in Central and 15th).
If you did not live in Mexico or in the US West, "Los Aztecas" will probably be the place for you. Still, I will recommend you try my other two choices.