I would definitely highly recommend Maria's BnB to anyone visiting Porto.
Location-wise, Maria's place is ideal. It is one block away from the river, right next to the iconic Palacio da Bolsa (the stock exchange of Porto) and close to other tourist stops, and next to a convenient shopping street.
The first thing we notice upon arrival was that the BnB is very clean --- Maria has certainly spent efforts maintaining it. The next thing was that there is a very complete set of kitchenware and ingredients -- oven, wok, dishes, utensils, seasoning, oil... tc. It was very helpful for us. Over all, every equipments in the house were all in readiness and in good condition.
Maria has been very friendly and helpful. We had a good time, and would be happy to visit again.