If you are looking for an immaculately clean place to stay, I can truly recommend to stay at Ana & Daniel’s.
The place was spotless and the shower amazing, big and also very clean. Furthermore it has good water pressure and boiling hot water instantly :)
Another plus was the location, just a short walk up the street and you have bars, restaurants and supermarkets. On the day of the arrival the picking up keys from the key box gives you autonomy and the freedom to improvise as you go. I strongly recommend booking a bike-tour (e-bike!!!) as one of the first things you do, as it will give you a good feel of the city and which places to explore over the next days.
Try out the grilled sardines and tomato salad in the “A Tasquinha dos Guindais”!
I followed the good advice of a previous guest on bring slippers or warm socks, as the floor can be a little cold (out of season) before you get the place warmed up.
Very recommendable for a long weekend in Porto!