Barbara's apartment is comfortable, has a great view, and is very well-located. I enjoyed my stay. The neighbourhood is relatively quiet for central Lisbon, although there were some noises from the street and building, but this seems to be a Lisbon thing, as I have experienced this (and more) at all three Lisbon Airbnb's where I have stayed. Another thing that I experienced, here and at all three (and nowhere else), is that the shower basin does not contain the water properly, and the bathroom floor gets soaked.
Barbara was very nice though and I really appreciated that she let me check out as late as I wanted. However, there is room for improvement on the organisational side. Before I arrived, it took several days to reach her, trying various means of communication. I had asked some questions about what amenities would be available at the apartment (particularly: whether there was something to prepare coffee), in order to decide what I should bring with me. Barbara said there were a coffee machine and a water boiler, but neither were present. When I mentioned this upon arrival, she said she would provide a water boiler the next day, but this never happened. Also, at check-in, Barbara's father, who brought the keys, arrived no less than an hour late. So, all in all, I guess it depends on the nature of your trip and personality whether this apartment is recommendable for you. I would probably book it again, because considering everything the price-quality ratio is good.