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.