The apartment is really great. The location is perfect for everyone who likes to discover the city by walking, most of the popular/stuff-tourists-need-to-do are pretty close. Considering it's really centrally located, it's also surprisingly quiet: no cars, no loud crowds. During the week, you got the kids from the school doing their thing, but that is only in the morning. So if you don't hate kids, this should be fine.
The apartment itself is bright and airy, the style simplistic but nice. Despite being under the roof, it didn't get hot (the October I stayed there was relatively warm with 24-27 degrees and sunny weather) thanks to all the windows. The kitchen has most stuff you need for cooking. I also really liked the balcony. It is narrow but it has nice views towards the city and towards the church.
Rui himself was an enthusiastic and helpful host who welcomed me when I arrived and was always easy to contact if something came up (like me not being able to open the door of the apartment, spoiler alert: I can only do the twist with the key with my left hand, the more you know).