We had a fantastic stay at Ana Clara's home! This is an unbeatable location. It's right in the middle of Baixa, steps from the Elevador de Santa Justa, Praco do Comercio (where you can catch the bus to Belem), Largo do Carmo; and easy walking distance to Alfama (Castelo de Sao Jorge, which you can get a glimpse of from the window); Se Catedral) and Avenida de la Libertade. When you walk out the front door, you're on a bustling street with lots of energy, and everything in walking distance.
The place itself is very charming and full of history. Ana Clara welcomed us herself and told us about the building and original beams that had been installed after the Great Lisbon earthquake. You can glimpse the castle from one of the windows, there are neat skylights, and a hammock.
The (very small) downsides: Ana Clara has fashioned a little kitchenette, but there isn't a full kitchen (not an issue for us as we wanted to eat and explore outside anyway), and the apartment is a number of flights (4 or 5 up), and no elevator in the building, so can be a little bit of a tiring climb (but we should be in better shape!)
The upsides far outweighed the small downsides for us. We enjoyed this apartment with lots of charm and character, a great host who's friendly and helpful, and an unbeatable location. Would definitely stay here again, hands down!