What I desired was a location that was not located in the city center but still well accessible by public transport. And I got it: the location is a few minutes walk away from either Marques or Guimares subway station. I preferred Marques because it is situated in a beautiful park wit nice surroundings (e.g. cafes, shops) and on weekend you have a flea market at hand (spoiler: also at other parks/places throughout the city).
What I desired was a place with a terrace to sit on after an eventful day. And I got it: on-top you have 2 pingo doce supermarkets in the vicinity as well as a grocery store across the street who stays open until 22.00. From the terrace you can view the church at the Largo da Lapa. If you decide to walk down this direction you will find a third pingo doce and if you proceed you will eventually enter the city centre (25 min walk).
But the best attraction of the appartment was its house keeper its manager. May I introduce: Irene. Irene is one of the loveliest persons I have ever met. She truly supports someone with everything you need. You need a restaurant - ask Irene. You need a taxi - ask Irene. You need new towels - ask Irene. You need suggestions or tips - ask Irene. Just write her a friendly message via whats app and she will take care of your problems/requests. She is highly professional and she runs the other 3-4 appartments too (there a 3 new buildings at the back also with terraces).
I enjoyed the stay there and in Porto as well - I did some of the usual sightseeing but I could also manage to stroll through the area of Lapa, Marques. Since I like discovering a city by feet I even managed to walk to the Parco Seralves (but traveled back by bus). Or went to the Estadio Dragao from the local football club. For people who like to stay a bit more where the "real" people live then I can highly recommend this place too. And if for some reasons you have to stay at home (appartment) you even have netflix :-).