We stayed at Mario's apartment for one night. It's a very small apartment but has all the necessary things you will probably need. Maybe apart from a stove or oven. We were greeted very warmly and received a small complementary bottle of Porto. Although Mario himself wasn't present that day, the host who let us in was well prepared. She gave us a map of Porto and did a very good job of explaining where we can see interesting things. That includes directions to a non-touristy restaurant with great food. There was no problem with leaving our luggage at the apartment after checkout. The apartment is smaller than we expected however cozy non the less. I recommend staying here and would do so again myself.