My family and I (6 adults and a baby) stayed at Malu's apartment during the World Cup for almost three weeks and it was our first time in Brazil. I contacted Malu for the apartment a year before our arrival, and I was able to Skype with her; where she was always available for our questions. Once there, her sister Senilda, was very friendly and available to help at all times.
The apartment is very clean and cozy. It's at a walking distance to the Metro station, the airport, buses and the beach. There is a local grocery store next door. We felt very safe and if we needed a ride, a friend of Malu would take us around for a fee.
The place has no air conditioning, but when we stayed there, it was breezy and the ceiling fans made it cool enough. I personally loved to lie down on the hammock.
Overall, it was a good experience. Malu and Senilda were very friendly and always concerned about us having a good stay. I would highly recommend their place.