Mario‘s appartment is located perfectly if you wish to explore Porto by walking like we did. It is decorated nicely and we had no trouble except for the dirty bathroom(s), which were not always left clean by other guests. Still, we could always chat with Mario and ask for tips since he does not live in the appartment himself. Overall, we would recommend the place for a short trip because of its convenient location! By the way, you should really have breakfast at the café he recommends. :-)