Mario's apartment was great value for money; it has all the kitchen appliances you could possibly need for a holiday. The room is small - as the photos indicate - but clean and modern.
Being given a map on arrival was very handy and the location of the apartment block is superb.
It should be noted that our apartment was on the third floor (and there is a fourth), although this is obviously not a problem if mobility is not an issue!
Overall Mario's apartment is a fantastic and cheap point from which to explore Porto.