We stayed only three nights in Porto and this was the perfect location! The apartment was nice and clean and you could not hear anything from the busy tourist street below inside. However, you might hear some noise from the neighbors as the walls are quite thin, but we were ok with that. It's the perfect location to discover the city, all the main sights are in walking distance. Dozens of restaurants and cafes right in front of the building (you really do not hear those!). We would definitely book this place again.