This place is a gem and what a luxury to have this much space in the EU. The construction of this flat is solid and there are many beautiful architectural details like a window that frames the road and ocean. The views couldn't be better.
Our family of four plus our nanny were very comfortable here. Quick access to the grocery store (just take the "public elevators" around the corner and you're there), fantastic restaurants and the heart of the city. The flat was spotless, had nice touches like Lisbon guidebooks and games, and was highly functional even with kids. There are lots of stairs (a foyer on the ground floor, a first floor and a second floor). We didn't have any concerns but something to consider if mobility issues.
Our host was highly responsive and helpful to our requests. We loved walking out the door and hearing languages from around the world (this area of Alfama is higher traffic, and you can hear voices from outside her and there - but it didn't bother us). We loved hiking around the area with our kids (3 and 7). They had a ball and were exhausted by the end of the night! We'll return to this flat again - hopefully soon.