Sorry I missed this thread the first time around... I lived in San Antonio around the later half of the last decade. And in San Antonio, Tex-Mex cuisine is highly recommended more than anything else. I lived way out in the north western part near the medical centre, and I am not too familiar with the downtown area, but from the touristy Riverwalk area, Acenàr
stood out in my opinion, from the quality of the food and the atmosphere. It is a bit off from the centre of hubbub, so a bit more quiet. Walk a few minute further PAST the better known and perpetually crowded "Rio Rio Cantina".. but there are a lot of "hole in the wall" type mexican joints if you can be bothered to wander off, even just a little from the touristy spot, where you can enjoy more authentic Mexican food for less.