We stayed at Joao and Vera's place for 4 nights in January. Joao is an EXCELLENT host - he always replies almost instantly with helpful information. The check-in was super-efficient, and Joao gave us a first-class introduction to the neighbourhood on the map. As many reviewers have already commented, Joao is more than happy to share non-tourist sights and shops if you are interested - and these are great tips.
The flat was renovated by Joao and Vera, who are architects. They did a great job of making a small space into a comfortable flat for a few days' or a week's stay. The bed is quite comfortable, and there is plenty of hot water and good shower pressure. The kitchen is small but has everything needed for a short stay - Joao and Vera very kindly provided some breakfast supplies, fruit and wine :)
The location is super, within walking distance of everything you want to see in Lisbon, close to public transport, and at the same time quiet enough to get a good night's sleep. All Portuguese properties are cold in winter, but the heaters provided did their job and we were warm and comfortable.
Finally, Joao and Vera were kind and flexible in letting us leave our bags and check out a bit later to get an evening flight.
All in all - an excellent stay, with super hosts. Muito obrigado, Joao e Vera, e parabens pelo seu sucesso!