I enjoyed my stay at the apartment for a weekend. It was bright and airy and well-located within the city to access the key tourist sites. There were plenty of great restaurants immediately downstairs.
Check-in and check-out was easy, and the host team was very responsive and communicative. The welcome bottle of wine was much appreciated! The apartment was well-provisioned with glasses, an espresso machine, and a good-sized refrigerator. Plenty of seating, including a dedicated work space. The apartment had both a portable fan and heater to help mediate temperature.
As other reviews have mentioned, street noise (downstairs restaurants, passersby, and trash collection) was an issue. Closing the wooden window shades made a significant difference to dampen the noise, although obviously that prevents you from keeping the windows open to enjoy the breeze. The other noise issue was caused by the fact that everyone coming in/out of the apartment building has to walk by the apartment's front door. Ultimately, I was able to sleep, but this is not the right apartment for a light sleeper.
There were a few cleanliness issues: the shower tiles looked like they could use a deep clean, and one of the bed's pillowcases appeared to have mildew stains on it. Finally, I had some issues with Wi-Fi speed; unplugging and re-plugging the router helped somewhat, but the speed would have still been low if you intended to work from the apartment.
All-in-all, I was happy with the apartment for a short weekend stay. The apartment is well-positioned in Porto and is the perfect size for two people. However, if I came back to Porto, I might consider staying in Gaia (for a quieter environment) and traveling into Porto instead.