I think we made an excellent choice with this apartment. I cannot imagine any better located base for your discoveries in Lisbon. It is max 30 mins from the airport with public transport, all train stations are easily accessible using metro - or even on foot - and you can start any walking tour from here! The neighborhood seems to be perfectly safe even late at night.
We had all the comfort for our 3 night stay here, and our host was very-very communicative. Actually we have not even met face to face as we could arrange everything via email/airbnb very quickly. We received the door access codes on arrival, so we did not need to worry about late check-in either.
There is a nearby supermarket if you are on self-catering arrangement, look for Pingo Doce - Chão do Loureiro next to the Elevador Castello. Alternatively walk out to Rossio or Praca de Figueira, both only 3 mins on foot, and you can find many restaurants and bars there.