I second the Hilton Morumbi in Sao Paulo. Food and service are fantastic, with a great view of Sao Paulo. As an example I took my wife and daughter to Brazil on Spring Break. My 15 year year old lamented that she wished we would have stayed 5 days in Sao Paulo and two days in Rio. I think it was the lounge and the staff. My wife and daughter said manicure was the best they ever had.