The place is close by everything, right in the center.
You have the famous restaurants 2 to 5 minutes away from the house, supermarket "Pingo-doce" around 10 meters away, the historic areas and night life all close by a walking distance from 5 to 15minutes and the bridges river and port wine caves around 20 to 30 minutes walking. If you want to go further the public transports are easy to catch as well, you do not need car to explore the city.
Regarding the apartment it is part of an old building (like almost all the houses in Porto) and it looks exactly like the photos so what you see/book it is what you will get.
The best thing is very quiet which is good to sleep at nigh.
I was there for five nights and I would not mind to stay there again in the future.