Overall, we enjoyed our stay at the Casas Brancas apartment. The apartment is very spacious and has a nice layout. Bernardo, the person who checked us in, was very helpful and gave us a few tips on places to eat and things to see...
That being said, the location can be a bit cumbersome to move around the city without a car/Uber. So, if you plan to stay there without a car or a cell phone to call an Uber, it may be time consuming to get to the downtown area of Porto.
The bathroom could do better as well: there were some mould in the shower walls, the shower curtain felt like it came from the dollar store (in contrast with the rest of the apartment), and the towels were not 100% clean. Also, there's no support for the shower head, which proved a bit annoying when taking a shower - you have to hold the douche with one hand while trying to clean yourself with the other hand - not practical at all...
As I couldn't find soap for the dishwasher in the kitchen, I left my dirty dishes behind, against my will. Also, there's a space where a washing machine should be installed, but there's no washing in the apartment. I had stayed in Airbnb apartments in Lisbon and Coimbra before going to Porto and both places had a washing machine/dryer available for guests...