Well, I've done the research. I've eaten the tacos. Now I can announce some true winners in this expanding field within Ann Arbor's culinary arena.
Tmaz Taqueria, on Packard near Banfield's; Taco King, inside Tienda La Libertad on W. Liberty; and Chela's, around the corner on Maple, all offer inexpensive light fare that highlights tacos--soft corn tortillas wrapped around a meat or vegetable, sprinkled with raw onion and cilantro and served with a lime wedge and salsa on the side. All three spots are individually owned and earnestly managed, with friendly, accommodating staffs. And each has positive and negative attributes. But the overall winner--serving food the most akin to what I've enjoyed in Mexico--is Taco King.
Though the cooks look Hispanic, Taco King is owned by Tunisians Saber and Sihem Naghmouchi. Perhaps because the menu wasn't written by native Spanish speakers, it uses English terms, listing tacos al pastor, for instance, as tacos with marinated pork. Traditionally, the filling for tacos al pastor is sliced from a vertical spit, as for a Greek gyro, but most places in the United States simply marinate and grill the meat. Taco King's version is the most flavorful of the three restaurants, clearly tasting of chilis, garlic, and fruit.