Pro: Best part is the location! Right in the heart of Alfama, next to the beautiful Se de Lisboa, close to many restaurants, and a short walk away from the south side (by the waterfront). Also not a long walk away from the busier area, Bairro Alto. Beautiful views from the windows.
Pro: The apartment was super clean! Hosts also very responsive.
Con: Biggest con, and the sole reason I wouldn't stay here again, is that there was a sewage smell in the kitchen, pretty much the whole trip. I was working in the kitchen and this was a big factor. The sink/drawers smelled bad, so I didn't feel like I wanted to use any of the cutlery or even use the kitchen.
Con: Older building, so these are minor - living room is small with a slightly annoying passage between the room and the bedroom. The washroom has a window to the kitchen which is a little odd. Flimsy shower head.
Other: I didn't mind because it's worth it for the view, but heads up - lots of stairs to get to the unit.