We've only spent one night at Mafalda's and João's place, so I can't say much about it, but communication with the hosts was very easy, the directions were clear, the room was clean and spacious and the flat is perfectly located if you have a flight to catch. The apartment has a bit of an impersonal hostel atmosphere since the hosts themselves don't live there and kitchen and bathroom are rather basic, but it's definitely recommendable for a short stay in Lisbon.