This place has two restaurants in San Martin, I believe. One is near the plaza and the larger one is on Villegas. We went (twice) to the second one, since it was closer to our hotel and it looked a bit nicer. The atmosphere might not be excellent, it is one of those huge restaurants, but service is good and they have an English menu (if you need that). The menu itself is huge and offers everything from all the meat you can think of, to pastas, pizzas, and local specialities.
The main dishes are reasonably priced, especially for San Martin. We had the Patagonian lamb for 2, which was very good. The salades are a bit expensive compared to what you get for it. The second time we went, we got the wild boar and deer plates. These were slightly more expensive and maybe not as much as the parrilla meat, but it tasted great, especially the deer.
We found this place to be a good choice in San Martin with good food and fair prices.