We had a pleasant stay in this apartment. The host are so kind and the communication is smooth.
The rooms are clean and well-designed. Most importantly, it is close to the Louis I bridge (just 3 minutes walk and you will be there). I walked to there every morning! Also, it is close to Sao Bento metro and train station.
Se Porto Cathedral is right next to the apartment too. Really good location!
Just one thing, the front door of the building and the apartment door are quite hard to open. But it is just some trivial thing.