We stayed in Sissi's apartment für 7 days this July and it was perfect from every perspective.
Sissi was already waiting for us on arrival and gave us a small Tour of the flat. Afterwards, she and her daughter Marta Provider a very detailed list of sights, Restaurants and to-dos in Lisbon.
The flat itself was absolutly clean and kept in a cozy style. We especially enjoyed the backyard where the temperatures were always very pleasant.
We would always recommend the Airbnb!