Depending on the brand cheeses labeled Quesadilla, or Asadero tend have a more salty flavor. I tend to stick with Oaxaca since some unscrupulous creameries label Monterrey Jack as Quesadilla and charge more for it.
- Queso Chihuahua: white, mild, melts really well like American cheese.
- Queso Oaxaca: white/yellow, stringy, melts okay.
- Queso Fresco: white, crumbly, mild, doesn't melt well.
- Queso Cotija: white, crumbly, salty, doesn't melt well.
Most of the time it's queso chihuahua people love — it's basically American cheese. Super creamy, smooth, wonderful.
It's soft enough you might think it was white american until you tasted it.
I know what you're talking about. But it's different from you can normally get. They get it from a food distributor. Just like you can never find cheeses as good as what they use at pizza places or burger joints. At subway they have american cheese that's amazing, nothing like store bought american cheese. Used to work at a place and the normal sounding things they ordered were just so much better than anything you'd find at a grocery store. Used to order this amazing blue cheese dip, I miss it so much, but you can't get it anywhere except from a distributor.
Hope this helps explain why when you try all the cheeses others have mentioned, none of them will really live up it to the real deal american Mexican restaurant white cheese dream.
Cotija is another great one that blows fresco out of the water flavor-wise. If you're ever thinking about oaxaca or fresco you should try chihuahua and cotija instead for better flavor/texture.
And as you surely know Mexican tacos don't have cheese, it's an American thing, but I love cheese on mine.