I was there on 15 Feb 2013, a Friday evening, with my girlfriend. At this day they only opened at 8:30pm. It was well attended, but not crowded, giving a nice atmosphere in the room with the chairs. If you feel like sitting on the floor in their other room, you could have a rather private dinner, no customer was using it at that time.
They don't label the vegan options in the menu, so you have to ask, and speak Spanish. But then they are very flexible to make a dish vegan, e.g. instead of mozzarella they'll use tofu for the chivito.
The chivito on a plate (260 pesos) was very good and I was happy to enjoy a traditional Uruguayan meal in a vegan version.
The doblado (215 pesos), my girlfriend had, was also very nice.
We also chose 10 small spring rolls (160 pesos) and a salad (200 pesos) as a starter.
Rather high prices, but also good quality and a very nice and attentive service, so absolutely recommended for a nice dinner in the evening.
Cons: No English menu, Vegan food not labelled, Prices not for a daily visit