We had a wonderful stay at Sara and Sergio's home. The apartment is perfectly situated on a street just on the edge of the loudest part of Barrio Alto and that made for a fantastic stay for us. (there was some partying but nothing like we experienced a year ago one street over, close the windows and shutters and we all slept well!)
We walked everywhere from the apartment - close to Principe Real, Chiado, Cais do Sodre and Rossio - and cafes and restaurants galore nearby. I got a manicure just up the street on Rua da Rosa - and did a little shopping too. Such a wonderful area, I am sure you will enjoy it!
The apartment worked well for us - one couple and a single traveller with us. The fans help greatly with Lisbon's summer heat and they provided towels, a hair dryer and all the promised amenities!
We are looking forward to being back in a year or two and would stay here in a flash.