We really, really enjoyed our stay. We loved the Sao Pedro neighborhood as it is a bit quieter than the busy town center - but it has lots of historical sites of its own to see and tons of great restaurants, cafes and shops (enjoyed by the locals as well). It is a beautiful walk into town (quite steep in places) and we liked being a bit removed from all the tourists. The location is actually very convenient for getting in and out of Sintra by car/Uber for instance to the airport, to the beach, or even back from Lisbon in the evening. Cascais and Estoril are easy to get to by bus (the stop is just at the end of the road).
The apartment itself is very pretty and the bed is comfortable. Everything is very functional and it was perfect for the two of us.
Sofia was a great host and communication was quick and easy.