We had an amazing experience using Airbnb, specially because of Marinho & Amelie. They made everything possible so we could arrive earlier than arranged, they even offered picking us up. The apartment is perfectly located near Castelo of Sao Jorge, we advice you to walk down to the city and use taxi to return since is so cheap. The apartment was excatly what we were looking for. It was cozy, new, clean, with illumination and ventilation. Alfama is at your feet and public transportation is a few blocks away. If you go during weekdays there´s a school nearby so it´ll help you to wake up earlier than expected, in addition to the birds in the castle that start singing kind of funny ;) I would definitely contact them if I return to Lisbon!