Pros: you cannot be more in the heart of Sintra. Right by the bus stops and gathering places, restaurants and sites. Grabbed the 434 bus to the castle and a tuktuk to the Quinta (you can definitely walk to/from the Quinta, just uphill on the way there). It's quiet at night when the tourists go back to Lisbon, no issues with outside noise. The apt was large and the windows and fans allowed a good amount of air/filtration. Beds are comfy and most things seemed new/updated. Rooms had plenty of storage space.
Cons, and none of this would stop me from staying again: They were REALLY nice but check-in was weird - they gave an address which is "close by", but we got yelled at by a guy who said "they need to stop giving this address!" (It's above ale-hop, accessed by a side door which they guide you to when you call.) The shower doesn't drain well, and the water temperature wasn't consistent. A few flights of stairs, no elevator. Some of the windows opened to weird locations, like bathroom window to laundry space and a hall window to a building's common space.
Overall we loved it here and would def stay again.
Side note about Sintra - parking is tricky. There's a one-way street before the NewsMuseum & Ale-Hop that we were lucky enough to get a spot at, stayed for 2 days for free. Parking fees have not hit those parking spots, yet! Research parking first and be prepared to park at a further, paid lot.