My family (4 people) stayed at Nuno's place. The apartment is really nice and the location is perfect: walking distance from the centre, really close to avenida de liberdade, good restaurants in the area if you are too tired to go around.
Margarida welcomed us with many nice suggestions and she was really kind showing us the equipment of the apartment. The kitchen is full equipped and the room are well furnished. The apartment has just been renovated!
the only cons is that the apartment is at the 4th floor without elevator (perfectly fine if you are not too old ;D)
I can only recomand it for your stay in Lisbon!