We loved 'living' in the heart of town. Just about everything is in walking distance and the metro is literally around the corner from the apartment. The street it's on is not a pedestrian area, so a little quieter in that way, but expect some street noise (sweepers, etc) only if you open the window in the front room at night. The windows keep out sound extremely well and the back bedroom was very quiet anyway.
It was wonderful to come back from a day of exploring and relax on the comfy sofas. The kitchen was well outfitted and we enjoyed our breakfasts in the dining room. Be aware the bathrooms are very small, especially the shower stalls (about 2.5 feet) and you have to climb three stairways up to the apartment.
There are several good and affordable restaurants on the same street, minimarts all over, and a big grocery store (Pingo Doce) within less than ten minutes walking. We would definitely come back!