The apartment is very clean and it looks like in the photos. The co-host, João was very friendly and welcoming and he gave us some tips on the area. There are also some maps and suggestions in the apartment if you need ideas on where to eat, etc.
It is very close to Martim Moniz metro station in case you need to travel further away and also very close to the station where the yellow trams are. Otherwise, you can walk anywhere from the apartment as most attractions are nearby (Alfama and all the amazing viewpoints, St Jorge Castle, Praça do Comércio, Santa Justa Lift, Bairro Alto where all the bars are, Lisbon Cathedral, National Pantheon, Rossio Square and many more).
Even thought everything is accessible and the area gets busy during the day, at night it gets quiet so none of us staying there had trouble sleeping.
Check out was easy as well as you just leave the keys in the flat. Additionally, if your flight is later in the day I think that you can speak with the co-host João and he can find a place for you to leave the bags. We left early in the morning of our check in so that wasn't necessary.