On the plus side, Juan and his mum are lovely people and the apartment was very clean. The bathroom was renovated and the shower is great. You're very close to Praia de Copacabana, two blocks (and you can see it from the window!).
On the downside, it's very, very noisy with the window overlooking traffic on Nossa Senora de Copacabana. The air con is an old model, it's noisy and pretty useless. The kitchen isn't great either, very small and cramped with two electric burners (I couldn't use both at the same time). I also felt a bit uncomfortable because there were many personal items in the apartment, hygiene products in the bathroom, clothes, bags, food in the fridge, etc.
I only stay for two days and I appreciate how clean the place was but I wouldn't have stayed longer.