Filomena and Walter's apartment is one of the best AirBNB experiences we have had. Filomena and Walter welcomed us on the evening of our arrival and gave us a detailed tour of the beautiful apartment, and the immediate surrounding area. They even helped us with our luggage up the stairs. They had left a lovely bottle of Portugese wine in the fridge, a fruitbowl full of fruit, and flowers on the dining table - a lovely touch to make us feel even more welcome.
The apartment is super clean and in a great location, very close to one of the main metro stations, Trinidade. But the walk into the old part of Porto is beautiful - we didn't need to use the metro to get around at all; everything you need is in walking distance. You do need to climb several stairs to get to the third floor, but it is worth it :)
We stayed with two couples - and there is plenty of room to be comfortable for 4 people.
If we were to come to Porto again we would stay in the same apartment if possible. Can't recommend Filomena and Walter's place enough.