Fantastic apartment, fantastic location. Everything worked perfectly well, the apartment is newly renovated, well furnished and spacious. Also: in spite of its great, central location, it was remarkably quiet.
The only drawback was some confusion on behalf of the hosts, who confused our reservation with someone else's, and expected us two days before the actual reservation date. They also weren't available for the check-in at the agreed-upon time, so we checked in by ourselves - they gave us the access code by email.
Also, they couldn't show any flexibility regarding an extension we requested just for our suitcases, as we had nowhere to leave them between our check-out time and our flight out of Lisbon.
All in, a great place to stay in Lisbon.