The apartment is great and it is in a great location to explore the city and the nightlife at Bairro Alto. If you are staying here (and you should) you cann't miss going to the Miradouro of Santa Caratrina and to the Jardim de São Pedro de Alcântara to be amazed by the views of Lisbon, all of them in walking distance from the apartment.
Most importantly, Maria is a great host and she will provide you with the best tips to explore Lisbon and make you feel more than welcomed.