We walked to Rosario's, 3-4 blocks south from downtown San Antonio. on the recommendation of a friend who used to live in San Antonio. It was easy to find, on the corner of St. Mary's and Alamo St. We got a carry-out order and took it back to our hotel. We each ordered chicken enchilada plates - one had creamy "suiza" style enchiladas, sweeter than I expected; the other was with the green tomatillo sauce (the best!). Flavorful but not hot. The rice was the best Spanish/Mexican rice I have EVER eaten in 50+ years of eating Mexican food in the southwest (the beans were good, typical refried beans). Salsa could have had more 'punch' or maybe we just got the mild salsa. Prices were good. The interior was eclectic, with painted concrete floor, 50's diner-style tables, chairs & bar stools, and lots of neon. It is a roomy restaurant with amble floor space, the patrons are not packed together elbow-to-elbow; it was busy but not packed.
We also ate at a Mexican restaurant our first night in town -- on the Riverwalk area. Rosario's was a far better bet. The food was considerably better, and there weren't as many tourists (yes, I say that even though WE were tourists) and, perhaps more importantly, there weren't pigeons waiting to attack the food on your plate, as on the Riverwalk!
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.