Everything was great! The apartment is not in the very center of Lisbon, but it is right next to the metro station, so the connections to all parts of the city are great. The airport is also only 25 minutes away by subway. The communication with the host was also very good, with quick responses.
I only have three notes: the room looks nothing like the pictures (I think it was renovated, and it is the same room, but the layout and coloring is completely different, still looks great though); the listing says that they offer luggage drop-off, however they do charge 5eur for that; also all the doors in the apartment are very loud and there are planes flying by constantly, so that can be a problem for light sleepers during the night.
All in all, I would definitely recommend Bairro Azul to anyone coming to Lisbon :)