The Pros: Ervita and Luz are the nicest people that you could ever meet. They make you feel at home. Communication with Ervita and Marly (another sister) is also very efficient. The apartment is very clean and nicely decorated. It shows that it has been newly renovated because the interior of the apartment does not match the exterior, as it is in an old building. Another plus is the closeness to the subway station, which is about 2 short blocks away. There are plenty of fast food places and supermarkets nearby.
The Cons: One cannot tell before one's booking has been accepted where the apartment is located exactly. This room turned out to be facing a large avenue where big trucks pass by intermittently all day and night. (There is another room for rent that is facing a courtyard and that one must be very quiet.) I am a moderate sleeper, and by the third night I was able to sleep through the night with only a few interruptions. Another drawback is the bed. After two nights, I developed a serious back muscle ache, so I slept on the floor for the next 7 nights. It is quite possible though that other guests may not have a problem with the bed.
Overall, the pros mitigated the cons.