The apartment is located right in the centre of the centre of the city, with a lot of the main attractions and interesting neighbourhoods very close by or through easy access on foot or by metro. Still, it's in a quiet street and a likewise quiet building. If you are looking for a "genuine Lisbon neighbourhood feel", this is probably not the apartment for you, because stepping outside you are likely to be surrounded by tourist crowds. But for spending some days, visiting the sights of beautiful Lisbon, or for work (as I did), it is perfect.
João was a very attentive host, gave good local tips, and communication was seamlessly fast.