I too found the tacos to be extremely greasy in my (admittedly only one) experience there. Try Washington Avenue a couple blocks south of La Lupe. Taqueria Veracruzana was the first (to my knowledge) authentic taqueria in South Philly and, therefore, set the standard. I like it just fine, but a friend that spent a significant amount of time in Tijuana - with his Mexican national fiancee - tought it fair to middling. Plaza Garibaldi - my favorite of the lot - is across the street and a little more upscale. Excellent queso fundido (better than Los Catrines). Rio Bravo - a little further west - is a little more ambitious and does some seafood dishes. Elsewhere in the city, there's a couple of places on South Street - the one that's NOT El Rey Sol is supposed to be better. And don't forget Las Cazueles, which I'd put at the next level, and Los Catrines (of course) and Zocalo at yet the next level.