Visited for a month. Apartment is perfect for long stays. Separate laundry and dryer machines. Space heaters and room ac/heater units worked well for February when Porto is colder. Fully equipped kitchen for cooking.
Location offers easy access to Porto and Gaia with minimal noise/tourists (lets you live like a local). Bakery around the corner is amazing (try the Pão de ló húmido, fried fish, and meat pastries if they have them). Local fruit/vegetable markets, butcher (for meats/eggs), and an upscale mall with full grocery store are all walking distance.
Walls/floors are a bit thin. Noise can be an issue as there are Airbnb units above and below this middle unit. Just message the hosts and they will sort out any bad behavior. Street traffic/noise is minimal.
For longer stays, recommend bringing an HDMI converter if you want to stream youtube/shows to the TV.