Since I was born and raised in Brazil, I figured I'd check out Samba to see how authentic they really are.
The concept (rodizio) is certainly Brazilian. The way that some of the meats are seasoned is "sort of" like we do in Brazil. The feijoada (black beans with pork pieces) is close enough to the Brazilian recipe, though not nearly as good as it could be. They have farofa (yucca flower with some seasoning) and it's pretty authentic. The cheese bread "looks" Brazilian, but the flavor and texture were far from the real deal. I heard that people go there for the grilled pineapple, which is fine, but not great.
Now... The meat variety is extremely limited. That said, I did not expect them to offer as many cuts as we do in Brazil. I did, however, hope that they would be pretty close to what other Brazilian steakhouses in the US offer (I'm thinking of Plataforma, Fogo de Chao and Texas de Brazil). Samba fails miserably on this category (the most important for a "steak" house). Moreover, the Gauchos did not know how to cut the meats properly. For example, the top sirloin (picanha) is supposed to be sliced super thin... I got a couple of very thick pieces.
The buffet is okay... I guess it caters well to the local demographic. It does not stand up to Brazilian standards though.
The service was the best part. My waiter was very attentive, friendly and prompt.
Overall, Samba is "sort of" a Brazilian steakhouse. The food is not bad, but really nothing to write home about.