Cristina's place is a great choice if you want to visit Lisbon. It's close to the city center, 5 min walk from Chiado, Baixa, and all the relevant points in town. Also, Metro and bus stops are really close, as well as Rossio train station (specially if you want to visit Sintra and Cascais). Cristina is a great host, she explained us in great detail what to visit in Lisbon and how to move around the city (metro, buses, etc). In the apartment there might be little humidity, but nothing serious as it's highly overruled by the comfort of the position and the place itself. Highly recommended!