We had a great stay over the Christmas holiday week at Valter and Natacha's flat. The apartment is great, superclean. Best was each of the three rooms had its own A/C-Heater unit with a separate remote. This was definitely needed as the December rainy season is quite humid in Lisbon, even if the temperatures are mild.
The kitchen is fully equipped, which is great as we prepared our own breakfasts daily.
The bathroom was also well-stocked with supplies. I even spotted a first-aid kit and a half a package of disposable baby diapers in the cabinet under the sink.
The only caveat is this is a 5th-floor walkup (or what Americans would call the 6th floor). It was tough the first day lugging the suitcases up 5 flights, but by the end of the week was hardly noticeable, as Lisbon is notoriously hilly anyway.
The balconies were great, we enjoyed having breakfast overlooking the street below. The flat is located in Baixa on one of the streets closed to traffic, not the main one.