We stayed for 3 nights in Mafalda's apartment in november.
It is big enough and well equiped for two persons, we had a warm welcome with plenty of advises for our stay. You really have a nice view to the riverside from the sleeping room ;-)
The apartment is very well located in the middle of everywhere. You can reach the metro in a 3 minutes walk, nearby are several nice cafes (good for breakfast). You can walk to Alfama, Baixa and of course Bairro-Alto, a tram stop of the 28 is also near by. During the night you can hear the tram and traffic a bit, but it was ok.
Communication with Mafalda was top and quick. Recommend this apartment for a stay of 2 persons for some days :)