We had a very nice stay at Claudia's apartment. Everything was as expected, it is just a brief walk to the train station of Sao Bento and a few steps more to the city center.
If we go to Porto again in the future, we will definitely keep the apartment in mind.
One downside was that the ceiling above the shower suddenly started to leak after a few days. We immediately let Claudia know, she informed us that she was going to follow up but unfortunately we heard nothing else anymore. Hopefully this gets fixed soon.
Apart from this, our stay has been great and Claudia was a good host who always replied fast.