We enjoyed staying at Sol's!
We were able to check in early/drop our bags off. Same for check out- Sol let us keep the key and leave our luggage there until the evening since we had a late flight. There is a kitchen where you can use the fridge and microwave. It is pretty quiet, with that being said, sound travels throughout the apartment. However, the bedroom is tucked away and you have some privacy which I really liked.
It is some work getting up the stairs to get to this apartment complex, however, as others have mentioned-most of Lisbon is a lot of walking and stairs anyway so it is probably the same for other airbnb's.
Would stay again :)