A taco is a tortilla and a filling, and almost every other detail is regional. Knowing which region a place is cooking from tells you more than any review.
Al pastor is Mexico City’s: pork marinated in chiles and achiote, stacked on a vertical spit with a pineapple on top, shaved to order onto small corn tortillas with onion, coriander and a slice of that pineapple. The technique came from Lebanese immigrants and the shawarma spit. If a place has a working trompo, order it.
Carne asada is northern Mexican and the default across the border states. Grilled beef, chopped, on flour tortillas as often as corn — the wheat tortilla is a genuine northern marker, not a compromise.
Fish tacos are Baja California’s, battered and fried, with shredded cabbage, crema and a squeeze of lime. San Diego and the whole Southern California coast do them well because Baja is a short drive away.
Barbacoa is slow-cooked, traditionally lamb or goat pit-roasted in maguey leaves, and in much of Texas and northern Mexico it is a Sunday morning institution rather than an all-day item.
Birria is from Jalisco — goat or beef stewed with chiles, served with a cup of the consommé for dipping. The griddled, cheese-filled quesabirria version that spread across the United States in the late 2010s is a newer variation.
Tacos de canasta, suadero, carnitas from Michoacán, cochinita pibil from the Yucatán: each belongs somewhere specific, and the places that cook one of them well rarely cook all of them well.