Daniel's apartment is great for a weekend in Porto. The location is fantastic. It's on a quiet street but easily walkable to everywhere in Porto.
The apartment itself has everything you need -- nice shower, outdoor area, kitchen, etc -- with a comfortable bed. We arrived late, around 11 PM, so the automated check-in was also very helpful.
The apartment has two heaters, but, can get a bit cold in the winter. So, you may want to bring an extra layer of clothing for the evenings.
Overall -- the apartment was nice and we look forward to staying there on our next visit to Porto!