My stay at Villa Lunae was PERFECT! I am a 7-year superhost myself, so I know all about airbnb experiences! Villa Lunae is in a perfect location (close to transportation and easy access to all tourist spots), check in/out was seamless and easy, the space was very clean, the patio was bonus, all amenities were provided, etc etc. I had an incredible experience here and I highly recommend it to anyone looking to visit Sintra!
As for reviews saying that it was noisy being directly next to the train station- take that with a grain of salt. Know that there is train noise and traffic below, and decide ahead of time if that's ok with you. The doors are quite sound proof. So when doors are open, yes you hear a lot of noise. But once they are closed, you don't hear much at all! This is for a guest to decide ahead of time, not something to be held against the host at a later time. Is being next to the train station a perk to you, or a downside? It proved to be a perk to me for my travels!!