You can stop looking for a place to stay in Lisbon because this is the place to stay. Not only is the apartment perfect, the hosts are incredible.

Prior to our arrival, communication with Gonçalo was great. He is extremely responsive and remained that way throughout our stay. We needed our return boarding passes printed during our stay and Gonçalo tried to find us an open place to print. When he was unable to, his partner, Ana, printed them for us and brought them to the apartment. They were both so wonderful and responsive, they are well deserving of being listed as super hosts if they are not already.
The apartment itself is in literally the best location. There are a ton of great places to eat within a 2 block radius and there are several public transit lines about a 2 minute walk from the apartment.
Be warned, the apartment is on the 4th floor up narrow steep stairs. It is worth the walk up the stairs though, especially for the view. Honestly, neither my wife are in top physical shape and the stairs were not a problem for us so don't let that keep you from booking this space. I feel like the pictures don't do the size of this apartment justice. It is pretty big for a city apartment and has a wonderful balcony with a beautiful view. It is very clean and has a well-stocked kitchen so you have anything you could need for preparing your own meals. The bed is very comfortable and there are many extra blankets and 2 space heaters in case it's cold during your stay (like it was during ours). The couch is also very comfortable for relaxing at the end of a long day exploring the city.
I can't say enough about how great this space is and how wonderful of hosts Gonçalo and Ana are.