Location is certainly a big plus, the owner is adorable and really willing to help.
Though 2 important remarks for those willing to stay here:
1. The apartment is small and does not fit for more than 3-4 persons in my mind
2. The apartment is located on a basement meaning that when all windows are closed there is a bit of smell and some mold in the air. In terms of security it is boarder line as it is complicated to sleep with open windows. Lisbon might be a very secured city but with kids it's a kind of risk that I would not take.