The apartment suited us perfectly - ideal size for two people and perfectly located. It is just a very short walk to Rossio for the train to Sintra, and also very close to tram 28 and the tram to Belem. The main shopping area is 5 minutes walk away and on the same street you have handy shops selling water and snacks as well as a very useful Pingo Doce supermarket. There are restaurants and cafés nearby but we mostly walked to Barrio Alto in the evenings, which is more lively. The apartment is well equipped and comfortable. Although the street can be a little noisy in the late evenings (we were there over a public holiday), it is not disruptive and you can't hear a thing once in the bedroom. It was certainly not a problem.
When we arrived Antonio met us as arranged and gave us useful local info and books, the owner was also very responsive when we had a little problem with the oven (user error!).
I would certainly recommend this apartment as a great base for getting out and about around Lisbon, and a comfortable place to come back to in the evenings.