GREAT location near many of the sites, restaurants, and bars in Porto. Nice, clean apartment with two floors and two bathrooms - which was really helpful for our group of 5 people.
If you're going there for the first time, I would recommend you get dropped off at the Starbucks on Rua de Mouzinho da Silveira and walk up a small number of stairs to the street where the apartment is vs. trying to drive or take an Uber directly to the apt. The street is awkward to get to, and is extremely narrow.
Also, remember to pull the door in when turning the key to open it.
Great stay - and great hosts!