I was on a 9-day-vacation in Lisbon with my girlfriend and all I can say is that Dinah and Carla were more than great hosts!
The place is in very nice and quiet part of the city with just 10-15 minutes walking from the nearest metro station and about 30 minutes from the downtown. The room was clean and tidy, as well as the rest of the flat (two toilets and kitchen). Although there are 4 rooms, everything was functioning flawlessly.
Carla gave us Lisbon's map and a few tips for making our stay unforgettable. She was super fast answering all our questions and was willing to help us in any way.
All in all, a wonderful, relaxing time over there!
Huge suggestion! :)