I spent almost 2 weeks in this apartment with a friend and we definitely enjoyed our stay.
Luís is a very nice host, his responses are super fast and he gave us really useful recommendations for our stay in Lisbon.
The apartment is comfortable and fully equipped, including good internet connection.
The location is very good, close to the city center (15 minutes walk) and to all public transportation (tram and metro just 2/3 minutes away from the apartment).
There are also a lot of good restaurants and grocery stores nearby.
I can totally recommend this apartment.