I had the miso covered Chilean Sea Bass.
Chilean Sea Bass is extremely hard to screw up because of its very high oil content. You can't really over-cook it like you can easily over-cook salmon, mahi-mahi, swordfish, etc. It's like the "bacon of the sea". The point is that the Chilean Sea Bass was very good but if I gave a piece of Chilean Sea Bass and a blow torch to a drunken bonobo, the outcome would be just as good.
The portion was small and it was expensive. But it's the only seafood restaurant inside the Rio besides the Rio Seafood Buffet. Given a choice between the two, go to the Rio Seafood Buffet.