We spent 4 night in this duplex and we really enjoyed the experience.
The place is really nice, very spacious and close to the center.
Joao and his wife are very nice people and totally helpful hosts. They will always provide you the information you need.
The only problem you have in Lisbon is to park your car but Joao gave us a better and much cheaper solution.
To conclude, I would totally recommend this duplex and at the end of our stay, we were really wondering if we would stay a couple of days more...If we come back to Lisbon, I guess we will choose this duplex again.