Two main, fantastic advantages for this place: (1) perfect location for exploring Lisbon's downtown on foot; (2) private locked parking garage right under the flat, perfectly matched for people having all their valuables carried in the car's trunk, like we had. These two huge advantages are all the reasons we needed to choose this place. Add a great hospitality, in-person check-in & guidance by hosts, and all you need under one roof, and you have a perfect base for visiting Lisbon on foot.
Just a couple of notes: I would say the place was perfect for a couple, but we were 4 persons, and with a fold-out sofa for extra 2 sleeping spaces it was a little tight for moving around the living room. We still didn't mind. Also - probably our fault and we've missed it - we didn't find the A/C, only a small fan.
Otherwise, this place is a gem.