Our stay at Juan's place was not perfect, but it was really close to perfect. Lisbon is an amazing city, and Juan's apartment just fits with it perfectly.
It is really charming, located in a very old and typical neighborhood, very quiet though very close to everything. Juan and Joao were great guests. We really felt welcome, and felt that we could ask them for help if we needed to.
One of the things that could be downsides for some people are the fact that there is no AC but only a fan. As a consequence it is either a little bit warm in summer, or a little bit noisy with the fan. But it is not a big bother.
The second thing is that is is relatively small, but this was not a problem for us, since it is very well arranged, plus in Lisbon you spend most of your time outside.
In the end this was one of my best accommodation experiences. I am looking forward to go back to Lisbon to stay again at Juan's place.