The apartment is centrally located close to Martim Moniz Metro station in downtown lisbon. You have to walk uphill a bit from the Metro (I recommend to take a taxi / uber if you carry heavy or larger luggage!). The apartment is very clean, well-equipped, with a nice bed with firm mattress, very nice towels (no shower gel / body wash / shampoo though). You should know that the bathroom is separated only by a thin glas door (bit frosted glas) from the sleeping area, so if you are not traveling by yourself, those traveling together should know each other very well, otherwise they WILL know each other well after the stay :-)).
Marco is a very friendly host and very responsive.
the apartment was definitely worth the money, we would stay there again on our next trip to Lisbon.