My friend and I stayed at Nuno's place for four nights. The apartment is as pictured - minimal, clean, well situated close to Baixa-Chiado or Rossio Station. The apartment is also very close to restaurants and bars so you will be spoiled for options. I had the room closer to the street. I was not bothered by the street noise but a light sleeper may want to take the room in the back instead.
Nuno was very responsive - he even called a taxi for us to the airport. He also made sure that we had coffee and was able to provide good restaurant recommendations. I would definitely not hesitate to stay here again.