We spent approximately a week at Alfama and we were very satisfied with our stay!
The apartment is centrally located and is easily accessbile with public transportation. (Note that the apartment itself is on the 4th floor and there is no elevator in the building.) The check-in and check-out went very smoothly offhours and the apartment was clean and in good condition (it was slightly smaller than the impression we got from the pictures). Would definitely recommend staying at Alfama to get the most out of Lisbon!