Palácio de Sant'Anna is a great place to stay.
The beast feature of this house is the location, you can literally walk to any famous spots within 20 minutes.
The closest spots are The Square with the fountain (forgot the name), the king with horse (forgot the name), marques de bombal and liberdade avenue.
Secondly, I was abit concern when the room is not quipped by AC (Air condition), but believe me because the house maybe build from stone, inside it feels very moderate, and if you open your window during night is cold.
Thirdly the hospitality, there was a key keeper guy named Carlos, he was real friendly and made my stay feels like home.
The house itself is super clean also you can cook, free washing machine, and wifi (of course)
And last not least, as you might get historical explanation from Maria about her house during its glory days !

Cheers