The apartment is beautiful and very well equipped. It's in a great central location but still residential so a little way away from the noise of bars and clubs at night. A small warning that the stairs are very steep and so if you suffer from vertigo or have knee problems etc, this might not be the place for you. Rossio station is a 5 minute walk from the apartment and the Baixa-Chiado and Rossio metro stations also close by.
Our recommendation; don't walk through the Baixa area and randomly pick a restaurant, it's a huge tourist trap and the food is both expensive and terrible. Ask for recommendations (some of which you'll be given at check in) and you won't go wrong. Alternatively there's a supermarket not far from the apartment and so you can always cook, drink and soak up the views over the city instead.
Really excellent service and a beautiful apartment. We stayed for a week and were very happy.