I just got back from a long weekend in San Antonio where I patronized three restaurants based on reviews from this board. In the spirit of giving back to the community, I am posting short reviews of my experiences.
I wouldnt classify Acenar as Tex/Mex exactly, but rather would put it in the southwest modern category. The menu and dishes reminded me of Dallass Star Canyon in its heyday.
The atmosphere at Acenars is mid-century modern, with a tendency towards the second half of the 60s. There are lots of day-glow oranges around, along with the requisite cushions and pillows. The balcony overlooking the Riverwalk is probably the least retro part of the restaurant, but the modern influence is felt even there.
The menu is unique. You can find a few seemingly standard tex/mex dishes listed, but when you look a little closer you discover that none are really that standard at all. I had the lamb shanks, which were minty in a somewhat non-standard way, served on plantains with a roasted onion and a Mexican cabbage slaw. The flavor and texture were wonderful.
My companion ordered a steak, which she asked for medium well. Rather than the usual Texas response to this order (well, Maam, we cant guarantee the quality of a steak cooked more than medium rare), the waitress happily accepted the order and delivered a steak that my companion was quite happy with in all respects.
The prices at Acenar are in the mid range. Dinner for two (including 5 hand-shaken margaritas) came in right at $100 with gratuity. I wouldnt feel comfortable here in jeans, but slacks and a nice shirt is standard for guys, a tie and/or jacket will place you in front of the pack.
In summary, Acenar is not the place to go if you are looking for traditional tex/mex, but there is great food to be had here in the southwest style.