My wife & I found the apartment with ease, only a short distance from the Aerobus stop, and after climbing the stairs to the fourth floor, met with the owners agent who made us welcome.
Our first impression was, as the main rooms face south, of a light airy feeling, the photos on the web site are very accurate, as the windows were open the traffic noise from the street below seemed initially invasive.
The apartment is spacious & comfortable with a well equipped kitchen. There is a mobile wi-fi for the guest use, which has sufficient speed for basic browsing.
The location of the apartment is excellent, within a short walking distance of the Praca do Comercio where you can pick up many of the tourist tours, and has very good transport connections to the rest of the city.
My early comment about the traffic noise wasn't an issue once we had settled in to being city inhabitants - and you can't expect any thing else when you live in the city centre.
For us, from England, Lisbon in October at 24degC with sunny days was great, we were, due to the apartments central location, to explore on foot to many of the cities attractions.