We stayed in this apartment for 1 month, and would highly recommend it.
Firstly, Gonzalo is a true Airbnb host. He will give you the story of the apartment and the neighbourhood, he has great local suggestions and is very responsive and attentive. He ads some nice personal touches that really make the stay.
The apartment itself is spacious and breezy and brilliantly located. Walk just a few mins and you will be in the heart of Alfama, it's about 15min walk to Praça do Comércio and the Santa Apolonia metro, 2mins away, will have you to Cais do Sodré in about 15mins as well. It's super easy to find your way back to from anywhere in the city, even late at night.
Alfama is very peaceful and there is lots of local life (during these covid times, at least — different vibe if the cruise ships come back I imagine). I will leave the local suggestions to Gonzalo, but you can be sure that there will be so much see, eat and drink in the immediate area, and of course the whole city.
We change city every month and after a month at Gonzalo's place, we can safely say that Lisbon is one of the best cities in Europe, and we are so glad we spent it in this apartment!