My wife and I travelled to Porto in Nov18 from England. We communicated with Claudia from HomePorto when we arrived at the airport and she was waiting for us outside the apartment in the street which was really helpful as we weren't sure which apartment block we were looking for.
Be aware that the apartment is down a quite a steep street which is expected as the whole Ribeira area slopes down to the Douro river. The area is vibrant, lots of local shops and restaurants and also felt safe at all times.
The only downside for us was the noise from the people in the apartment above on Fri & Sat night which went on until the early hours. However, on Sun and Mon night there was no noise from above at all so maybe its just at the weekends but I guess you may expect that in an apartment block.
We found the location excellent to explore the area, from the port lodges across the main bridge, the restaurants on the riverbank, the fantastic churches, and the main city centre.
Sao Bento metro station is about 10mins walk and we used it to get to/from the airport and to see an FC Porto game at the Dragon stadium which was fantastic (my wife especially liked the shopping mall adjacent to the stadium!).
For 2 people the apartment is perfectly proportioned, and we especially appreciated the Netflix, WiFi functionality and especially the bottle of wine on arrival. Note that the apartment is on the 3rd floor (out of 4 floors) and access is via stairs only. This is to be expected in such an historic building and you will need to get used to doing a lot of walking around the city anyway.