The menu description of the picahna at MuQueCa on Cambridge St in Cambridge says that the sirloin cut used is prime, and I'm inclined to believe this. The ~8 oz steak, ordered rare, was served more of a medium-rare, but due to the extreme intramuscular fat content, this was probably optimal. The steak was juicy and perfectly salty (I am a salt lover, but Brazilian meats sometimes lean towards the ueber-salty & dry side). A nice 1 cm belt of fat surrounding the steak also made for good eating.
I suppose this dish doesn't really qualify for a proper steak frites because the frites are just Sysco-type crinkle cut fries. I think the dish should get a pass, though, for two reasons:
1. In addition to the crinkle fries (which are served unsalted and are perfect for soaking up the copious scallion-infused steak juices), the steak comes with a generous portion of stewed black beans, a cup of pico de gallo and lots of scallions, a plate of that delicious oily rice they serve there, and farofa. For $3 you can add a bowl of expertly-prepared (just barely cooked, salt and oil, no bitterness) shredded collard greens.
2. It's $14. C'mon!