We stayed for one night at Casa Azul hostel and found it to be a very comfortable stay. The hosts are fantastic - they let us leave our luggage while we explored Sintra, the breakfast provided was excellent and they are extremely friendly and welcoming people. The only slight inconvenience is the bathroom - although there are two showers, they are in the same room, so effectively only one person can use them at a time, resulting in a slight wait at busy times. This is only a minor concern though and did not detract from an excellent stay. A great place to spend a night or two while seeing Sintra!