Joao's flat is really lovely once you get past the point it is tiny. Considering most people rent it to only sleep in it, it is perfect for two sharers or couples. It is well equipped and I believe much better than a hotel.
The flat is very near Apolonia station with great connections to the airport and everywhere really. Walking distance from the castle and the night life in Barrio Alto.
Joao is a great host too and let us check out around 5pm which has helped us enormously and we are so grateful for. I would definitely recommend the flat and would like to stay in it when I return to Lisbon!