I've been to other cities in Brazil on business but never Rio. I recall the food as superb (on an expense account) and the people as friendly. Traffic in San Paulo was the worst I've ever seen. We spent some time in a few different neighborhoods and played some pickup soccer with some kids who very ~very~ good. My family came over from Portugal not all that long ago so it was fun meeting people who could actually pronounce my name. Monetary inflation at the time was crazy. I went to a bank to change money & they suggested a second-floor place nearby that would give better rates. They said to go quickly, because the exchange rate was changing hourly.
But Rio itself has a very bad connotation in my family. A young cousin (~25 yrs old) visited there about 20 years ago and was murdered at a bus stop, apparently because he didn't want to surrender his watch. Quite a shock.