Great location in the Sao Bento neighborhood—close to restaurants, cafes, bars, outdoor kiosks, etc. and easily walkable to the main Cais do Sodre train / bus station. Windows open up to the main road, but not a lot of noise. Similar to many Lisbon homes, no central heating so can be a bit cold in the apartment (there are two space heaters provided).
Unfortunately when we were here there was construction happening in the apartment below that could be very loud during the day (luckily we were out exploring most of the time they were doing construction) and the work resulted in a strong sulfur smell that came into the apartment (not the fault of the host, just unfortunate because there really is nothing to do to fix this).
Overall, it was a good apartment for three people spending a few days in Lisbon. The location is really what makes it stand out! The hosts are responsive and good communicators as well.