Marta is a great hostess! From the moment I inquired about the apartment and through my check-out, she was always prompt with her communication (both via Airbnb e-mails and WhatsApp messages). She answered all of my questions as quickly as possible, and even took the time to check on me after my first night in Lisbon.
The location of her apartment is fantastic! It's less than 5 minutes from the Baixa-Chiado metro station. I estimate about 5-15 minutes walking from a variety of restaurants. And about 10-20 minutes away from exploring other neighborhoods (like Alfama or Barrio Alto).
The apartment itself is spacious, comfortable, and well-decorated! There is room for up to four people, but be aware there is one bathroom.
One of my critiques is that the apartment could use more mirrors. There was only one tiny mirror in the bathroom. I would suggest putting another [full-length] mirror in the living room area, which would benefit as you're getting ready to go out.
Also, due to the central location, there is quite a bit of noise at night. Just be mindful of people talking loudly outside, and of the vehicles driving through periodically. If you are a light sleeper, definitely bring ear plugs!
I would definitely stay there again, and I certainly recommend this apartment to others!
Cheers!