I stayed at Maria's for a whole month, during January.
I can say it was a very pleasant stay.
The room was just like in the pictures, the apartment is very clean and cozy. The bathroom is very clean, the kitchen too. It's a three to five minute walk from the subway, and it's impossible to get lost there.
It's also at a walking distance from the center of the city.
Maria and Oriana are very polite, generous, educated and nice people.
I highly recommend reserving this room. Porto is a wonderful city, it was a great experience.