I had a very nice experience of staying with Frederico! He was very nice, approachable, communicative and he would help you with evrything you need. His flat is amaaaazingly beautiful!! Technically right there on the beach itself! Lol. Very close to main copacabana center, very easy to navigate around, buses, train, taxi u name it.
Highly recommended to anyone visiting Rio for the first time. Would come back again and stay with him if given the chance!