I would definitely recommend staying at Laura and Alejandro's apartment. It's a fantastic location to explore central Lisbon. Although it's not a huge place, they have made really good use of the space and everything you need is in the apartment. There is also free parking on site, which is very rare for this part of Lisbon. The apartment is in a courtyard off the street so there is almost zero noise from passersby, although you will hear planes flying over head from time to time.
Laura met us at check in and check out, gave us lots of great recommendations and was super friendly and helpful. A great host and a great apartment!