We liked our stay a lot! The apartment is very well situated and no street noise is audible. It's a very cool place to hang out and calm down after a long day. It's very luminous. The shower is very big and very comfortable to use.
On the negativ side, I could image that it gets hot during summer though, since it is on the top floor and the roof and walls are thin (there is air condition). This also means that you hear very well what is going on outside – passing airplanes are quite noisy (a problem that a lot of Lisbon has to deal with). In the back of the house, where one enters, two homeless people pass the night – but they won't bother anyone.