There are two things going on here: the place is a hole-in-the-wall, but it's serving mini-tacos and sopes like you might find at a hip, upscale restaurant downtown. They are finely crafted, and probably the best in DC. $4 gets you two mini-tacos, which are about half the size of what you are likely to find elsewhere.
They are not the kind of lusty, generous tacos or sopes you will find in the South Alexandria area where El Costalilla and La Mexicana have started a following.
In addition to the carnitas and al pastor tacos, I tried the tamale stuffed with pork and the vegetarian quesadilla (both of these are also mini). Filling for the tamale had little flavor, and the quesadilla - mostly tortilla and cheese- wasn't as satisfying as a really good papusa.