What can I say about Tiago's place? The title he uses on the flat advertisement says [almost] everything: the best location in Lisbon! Besides that, the house has really great amenities and you'll get to meet a super great host always prompt to reply any question you might have. And if you like to cook your own meals through your stay this is the place - don't miss on lisbon gastronomy though!
The only down side? My stay was too short!