Joao's place is fantastic.
The location is excellent- close to the train station, in the Vitoria neighborhood, it's incredibly central and beautiful.
The apartment itself feels brand new, including the stairwell areas leading up to the apartment. Everything has been beautifully renovated, it's very stylish, and very comfortable.
The bed was pretty comfortable, as were the pillows.
The internet was great- 30 mbps down and 30 mbps up.
The air conditioning unit does both heating and cooling and does a great job maintaining whatever temperature you'd like.
The bathroom and shower were clean and spacious, and the water pressure was great, with plenty of hot water.
Joao's mother, Norvinda, met us there and gave us TONS of fantastic tips. She was incredibly sweet, and very helpful. She checked in with us multiple times with additional suggestions and just to make sure we were enjoying our stay.
We would absolutely stay at Joao's place again next time we're in Porto- we stayed there a week and didn't want to leave!