The apartment is in a perfect location for exploring Lisbon by foot. The living room is cozy and has a lot of light. The only down-sides for us were the rather uncomfortable bed (it is pretty hard) and the small shower.
Additionally I would not recommend the apartment to people that plan on cooking everyday, the kitchen does not provide a lot of appliances, but staying in such a culinary rich city that should not bother a lot of people. There is enough tasty food everywhere. Besides the bed, we really enjoyed our stay and Sandra's apartment is perfect to stay in the heart of Lisbon.