I was in Lisbon for a business meeting and had a wonderful stay at the flat of Manuel and Teresa, which was in absolutely spotless condition, had a lot of flair and offered the promised quietude in the middle of the city.
It is extremely well connected through the close-by Marques de Pombal not only to the city centre, but also the university, the airport, Hop on-Hop off busses, even to beautiful Sintra, and many other places that may be of interest. I would stay the flat any time again!