I stayed here for around 5 days and I had a pleasant stay. The Airbnb is in a dorm-style type of building where there are multiple bedrooms with shared spaces and bathrooms.
The facilities were always clean and I didn't have any issues using the bathrooms, same with the kitchen. There are also tables to eat at. The living room area was small, it was a sofa with a small tv.
My room was clean and spacious (at least for me 1 traveler). There was a big window that allowed air in but I will say there is no screen so bugs can get in. If that does happen, just ask the front desk for an insect spray. That helped me the next couple of nights I was there.
The bed was very comfortable. The other thing is that my room didn't have a dresser to put my clothes in. There was a clothing rack. Additionally, there is no AC in the room so if you book in the summer take that into account.
As for location, Lisbon is a very hilly city and the Airbnb is on top of one of the hills so it is a steep way up if you have luggage. I'd suggest getting an uber from the airport if you have luggage. Uber in Lisbon is pretty cheap (5 euros from the airport). It's about a 10 min walk from Rossio square which is the center of the tourist part of Lisbon. I had no issues getting around except when I had a lot of things with me and had to do the climb up. There are a couple of restaurants in the Santana street as well as a couple of mini supermarkets. I loved the location of the airbnb, I realized that while I was there it was nice to stay somewhere that was more residential away from all of the touristy traffic but still being close enough by walking.
For any female travelers, Lisbon is a very safe city. I will say there aren't staff onsite during the night time so you might feel uneasy at night if that matters to you. My first couple of days I felt uneasy since I was traveling alone but nothing happened and everyone in the Airbnb kept to themselves. But overall, I had a very pleasant stay, I'd book again. Thank you Maria for your help!!