AirBnB helped us to find rooms despite of the overbooked situation in Rio. We contacted Ana and got a reply just a couple of hours later! Everything was flexible and smooth which makes things much easier for us.
The house is situated on the top of St. Tereza and it is the perfect place to chill. Wonderful garden, nice living room, hammock. The bus is leaving right next to the house, which is convenient as you are not in walking distance to the main attractions.
The room is clean and functional. the matresses feel like clouds, probably not everybody's taste but for me OK. The Corcovado can be seen from the room, which is nice.
The breakfast is really marvellous. All kinds of breads and cakes, fruits, jam,... Be sure to be there on a Sunday, when breakfast is served to the general public and get to know the neighborhood.
If you want to have a true brazilian experience than you should stay at Ana's house. I could imagine it to be a top place to learn some Portuguese and get to know the country and people! I wished I could have spend more time at their place.

PS: If you are lucky her son Joao can give you a short Favela tour. The insight to Favela life and the view from the football field on top is priceless!