I spent 4 days at Antonio's place, with friends, and I have to say it was amazing.
Antonio's mother welcomed us the first day: she is a very happy and sweet person, she gave us a lot of good advices and tips, so that we could enjoy our stay as much as possible !
The flat is great, and the little patio is amazing to have dinner and drinks, after a long and sunny day. The flat itself is amazing : big, nice and fresh. I think it is probably the first airbnb flat that looks even more amazing in real than in picture !
Last, Antonio is a very comprehensive and flexible host, really reactive.
I strongly recommend this place for the ones who wants to enjoy a nice stay in Lisbon :)