The Monkey Flat is the perfect place to stay in Lisbon. We stayed for a full week, and is really was ideal. It is near to two train stations (Alcântara-Mar and Alcântara-Terra) as well as many bus/tram stops so you can easily get around the town from the flat.
Marina has thought of everything, the flat is very well equipped (iron + ironing board, hair-drier, fist-aid kit, stuff to make tea and coffee, toaster, dish-washer, washing machine, ...).
It's also beautifully decorated and must have been recently renovated. Very clean. The little courtyard at the back with table, chairs and a hammock is a huge bonus.
You can hear the planes flying over the city during the day, but at night it is very quiet. We slept really well.
Marina was out of town when we stayed but was in contact with us by message and phone. We were greeted by Rita and Claudia who were very welcoming and showed us around. We would definitely stay here again.