Great value and excellent location - very close to neighborhood cafes/restaurants, Tram 28, Jardim de Estrela and within walking distance to Campo de Ourique or to the city center. My wife and I stayed/worked out of here for a month between Nov/Dec 2018. Overall experience was positive and Sofia was an excellent host and very accommodating to our needs. She made sure that the internet was fast and stable and provided a wifi hotspot as a backup.
Few caveats you should be aware of... The unit is on the 3rd floor and it can challenging, carrying a heavy suitcase up the stairs. Construction is ongoing next door, and considering the slow progress I saw, I suspect it will continue on for quite some time. Lastly, the apartment has space heaters - it can be a bit chilly depending on the time of the year that you visit.