This is a beautiful apartment, and its location in the city is ideal for exploring the riverside and downtown central areas of Porto. I loved the neighborhood-y, charming vibe of the street it's located on (e.g. locals in the building across the way hanging their laundry). The apartment itself has all the basics you need and a very nice amount of space for two people or even four.
Since no one was staying there the night before I arrived, Elisabete was able to arrange an early arrival for me for 30 Euros extra charge (I was coming in from the US on a red-eye flight) which was very much appreciated. Unfortunately when you click for directions out of Airbnb the address is incorrect, and I had to walk .2 mi to get to the right place, so my advice to future travelers is don't use that button! And/or make sure you communicate with the host well in advance.
After that small issue, Joao met me at the space, provided local tips, and was generally really amazing at being responsive! For example, I had a tough time using the key to the outer door and had to message him at 1:30a, and he came very quickly. He even came back later the next day to really show me how to use the key...with a bottle of wine, which I'm not sure I deserved! Joao was really great.
One thing that it's important to know is that there is ongoing construction in both buildings that surround this apartment. If you are the kind of person who gets up early (like around 8:30a) to go explore the city, this will be no trouble. If you are thinking of sleeping in on any day other than a weekend (they don't work Saturdays and Sundays), another place might be better.