Went back to Granix this year. The buffet is no longer "eat all you want" but is weighed at the cash register by the kilo. It does stop one from eating too much! They no longer have their wonderful soups but the food is still great and despite some other reviews, the salad bar is one of the best in Buenos Aires: very fresh, very extensive and very vegan. The cooked food is vegetarian, some vegan. The food is great and a wonderful place for lunch in downtown Buenos Aires, without having to resort to pasta or cheese in other restaurants.
Cons: long lines at lunch time (sometimes)