Me and my boyfriend spent 6 days in Joana's flat and had a lovely time during our stay.
The location is great (we could walk almost everywhere), and the flat is very charming and quirky.
Joana was also really helpful, giving us several options and routes to get to the flat, and tips for restaurants etc. We were also able to check in a bit early and leave our bags in the flat when we arrived which was great.
As the flat's in an old historical building, it can potentially be a little bit of a challenge for the vertically gifted, as the doorframes and shower are quite low. It is also kind of part of the charm of the flat.
We'd warmly recommend Joana and the Orange Tree House for a stay in Lisbon.