I spent here 5 days with my wife and my daughter during last Easter holydays.
Apartment very clean, fully equipped, modern althought hidden in the old Baixa district
Great location: town centre and many touristic attractions within walking distance, all sorts of restaurants, pubs and little grocery stores nearby. (I recommend to have breakfast or brunch at "O Ninho")
Maria is a very very nice host: always available with text messages, full of tips and advices and helpfulness (we arrived in Lisbon very late in the night, due to the delay of our flight, nevertheless she waited for us at the apartment; she even booked the taxi for us).
A great stay!