Boa Saude

Well, I've been to this place like a million times. It was one of my favorite restaurants in Brasilia, but I feel it lost some quality over the last 3 years.
That said, I still think it is worth a visit once in a while.
They have a great variety of salad and hot dishes. Asking about the vegan ones is highly advised.

Updated from previous review on Wednesday June 26, 2013

I went to Boa Saude after almost 2 years and I felt it was really good again. There are notes to tell if the dishes contain milk or not and pizza with Mandiokeijo, a brazilian vegan cheese. Their store also went through some reparations and it is more organized. There's a lot of vegan/vegetarian stuff to buy.

After 9 days of traveling in Brazil, we have seen a whole range of these vegetarian buffet restaurants, and Boa Saude is definitely one of the better ones. The choices (specially cooked items) were much better. Also, one of the girls spoke English which made it easier. The pricing too was much less than many of the other similar restaurants. To reach the restaurant one has to transverse a very depressing lobby / indoor passage of one of the typical, generic office buildings found in Brazil. But once you reach the restaurant, it is bright, large and has a semi covered patio as well.

There's an example of a family running business.
Not open on Saturdays because they're 7th day Adventists.
In these days find other option nearby.