We enjoyed our stay in the apartment, Antonio was very friendly, helpful and asked if we needed anything. The rooms are very clean and we used the kitchen quite often, which has everything necessary (except maybe very sharp knifes and spices). There is a desk as a good workspace and fast wifi!
After you use the bathroom you might open the window, so there is no muggy/chlorine smell of the drain, but for us it was okay.
The location is very nice, right next to the metro station (windows isolate noise very good) and supermarket and in walking distance to the downtown. For the check-in, unfortunately, you need to go somewhere else to pick up the key, but it's just a 10min walk and you get very good descriptions for everything!
I would recommend staying there, because it's a quiet and relaxing home if you need a break of the busy city Porto and don't want to live outside the city.