We had a very nice time at Joana's and Irene's flat. The place was spotlessly clean and exactly as advertised. For two people it was quite roomy. The bathroom was a bit on the smallish side, but usable. The windows are modern double, or triple glazing so that hardly a sound enters the flat.
The flat is very well situated and only a short walk away from the transportation hub of Santa Apolónia railway station. If you have heavy bags, there are two bus lines, 712 & 734, that take you in two short stops from the train station (starting from the corner of the Military Museum) to a stop right in front of the flat. From the train station you can also take the Metro (Blue Line, Linha Azul) as well as several buses, notably the 728 that takes you in one direction directly to the Parque das Nações with the Lisbon Oceanarium and in the other direction to Belém with the famous Jerónimos Monastery and the Torre de Belém.
The owners were helpful, quick to reply to any questions and very accommodating about our check out time. Thanks again, Joana and Irene!