This is a great place to stay. We (me, my husband and our 7 year old daugther) spend 8 days in Alvaro's place during Christmas and New Years. We arrived at Christmas evening and the next day all shops were closed so Alvaro arranged groceries and ordered a special Christmas bread for us ( a Bolo Rei). That was a lovely welcome! Alvaro's place is super clean with a fully equipped kitchen. It has a dishwasher, espresso machine, washing machine and water boiler. We made dinner several times (and got delicious meat from the local butcher downstairs). Alvaro made sure there are enough blankets and towels in the apartment.
The neighborhood is quiet and cozy. We walked easily to the nearest Metro station (Heroismo) or strolled to the old city center. Great food and food shops are everywhere (do not forget to buy some high-quality port, olive oil or their famous marmalade!). We definitely want to come back to Porto!