I stayed for 7 nights and had a very good time. The garden is gorgeous. The place was clean and tidy. It's a very budget-friendly option for staying in Lisbon. I liked the area around the apartment very much. It's close to some very good restaurants and cafés, as well as close to the Metro and busses that get you to the center and tourist areas very quickly.
The room itself was rather small and dark. But since I only used it for sleeping, it wasn't a big problem for me. The apartment is being shared with other guests, so it can happen that the kitchen gets a little messy or the bathroom is occupied.
Communication with Madalena was pretty good. There was a small problem with my check-in but in the end everything worked out fine.
I would recommend staying in the apartment if you are travelling on a budget and don't have super high expectations.