We stayed at Mário's place for 3 nights and it was really nice there.
Check-in went really smooth. The house is easy to find, once you found the Clerigos Tower (which you can't miss) and Mário's friend welcomed us and gave us a map and tips where to go. Check-out was really uncomplicated as well.
The location is awesome, you can walk almost everywhere you want and the house is right next to the Clerigos Tower (where everyone should go up - awesome view! but do it before 10, afterwards will be a huge queue). Supermarket, bakery and restaurants are right around the corner. There are really no huge distances from this location.
The apartment is big enough for two people, the bed is huge and comfortable and it's overall very clean.
We would definitely stay there once more if we get the chance to!