WE spend 3 nights here. it is centrally located, like you could not be better situated. Everything within walking distances. The place is wonderful, beds super comfy, sparkling clean, rooms well decorated, everything we needed in the kitchen. We spent many hours in the living room with the windows open watching the views.
A couple things to note, and they have been mentioned and we were aware and ok with that. Many steps to reach the apartment that allows for the wonderful views. Good workout ;)
No AC, or none that we saw. For us it was April but we were lucky enough to have a day of 28... IT was warm, fans were provided which was awesome but in the warm summer months something to be aware of.
Also we already were aware, bring earplugs. Depending on the days a lot of music in the square and sometimes very late. unless you are out partying also.
All in all we had a wonderful stay here, Porto is a hip, happening place. Great food, shopping, views, activities.. And this place is were to be.