Good location, close to many tourist attractions, the Baixa-Chiado metro station as well as Rossio train station. The location might not be great for the 'older' tourist and tourists with reduced mobility as you would need to walk up steep hills/a lot of stairs to get to the building. There is a free elevator almost next to the Elevador de Santa Justa, which can save you some energy, but it only works until 21h00.
The apartment is in an old building which means you can hear the neighbors above walk around their apartment, but it didn't bother us. The street is pretty quiet at night.
The apartment did not have airconditioning but there were two fans, so if you like to be in a really cool place when it's really hot, this is not for you.
We had a late flight and could leave our luggage at the office of the company that rents out the apartment, that was really great.