Let's talk about the positive first! The apartment is great for two, very compact but comfortable and pretty. Everything was clean, bed sheets, towels and all. Great bathroom, good shower with amenities (shampoo, conditioning, bath gel), and also a hairdryer. The kitchen is also nice, which includes all the essentials, including coffee capsules (which we didn't use, but it was there). Unfortunately, the cooktop wasn't working. Great response from António as well, really fast and friendly. It was really nice of him to let us have an early check-in.
On the negative side, even though we knew it didn't have AC, it was really HOT in Lisbon. There was a little fan available but it was not enough to sleep, also because of the noise. It's not comfortable having to bring it with us every time up and downstairs. Especially for a tall guy like me, since the ceiling in the bedroom is really low. So it's something to think about (I don't know if it's possible to install AC on such an old building). The privacy is not good either, if you want to leave the windows open because of the hot weather there are people looking at you in the apartments right across the street. And if you keep them closed, you already know...very hot. At least in the winter must be a great place, since they have heating.
About the neighborhood, sometimes we didn't feel safe walking back to the apartment at night time as we felt at other places in town. Putting that aside, still is a good location (public transport wise). The streets are very steep to walk, so it's not a great place for older people (the building doesn't have an elevator).
Overall, the city is amazing and you usually get home so tired that you don't even care at the end of the day.