We had a great time in Casa São Miguel. Pedro was extremely welcoming and went out of his way to ensure everything was OK at all times, he even booked us a taxi on our last day!
The apartment was clean and exactly as portrayed in the photos and description, small but functional with a fully equipped kitchen and bathroom with a shower. (Note: in Alfama you do not flush the toilet paper)
You cannot get a better location in Alfama (or by extension in Lisbon), there are literally tour groups taking photos right outside the apartment. All the best views are a 5min walk away.