Beautiful, spacious and cozy! Has everything you need and more e.g. juicer, logs for a fire, a heater in every room in case you get cold etc. Claudia was really kind and communicative, she gave us lots of recommendations and made us feel welcome. You can walk to the coast in less than half an hour by foot and explore the beautiful coastline (bring good footwear, it's steep and often requires scrambling!). There is an organic local supermarket a 10min walk away that also has lots of vegan and gluten free options if this is required. Also you have the best restaurant literally next door (definitely try their cookiecake for dessert!)
Just a note on location/transportation - We think it would be best to have a car when staying at this apartment, as ubers/taxis/buses were less frequent than expected and often had very long wait times. It took us between 30min-2hours to get back into Sintra and varied considerably everytime we needed to get somewhere so it was difficult to plan around this - although this might also have been due to the dates we were staying. Although, as mentioned Claudia is super friendly and even offered to drive us at one point.
Overall would definitely recommend!