In one word: Excellent!
The apartment is situated between the attractice Barrio Alto (uphill) and the main boulevard "Avenida da Liberdade" (downhill). I stayed there nearly six weeks.
The apartment itself is very nice and equipped with everything you need. It is clean and well maintained. The double bed is very comfortable. The small terrace really provides a very nice view. I enjoyed my stay very much and if I ever come back to Lisbon I will ask whether this place is available.