Stayed at the apartment with my siblings and our partners to hang out together for a week and enjoy Sintra and the surrounding area. We visited Lisbon, Evora, Obidos, and Nazare. The apartment was really nice and very well located. We could do a lot by just walking around or taking a "tuk tuk" when needed. It was really hot during our stay, the apartment only had one fan that didn't work really well, but the host promptly got us a new one. While it is ventilated and it gets cooler at night if you leave balcony doors open, it gets pretty loud in the street in the morning.
One other note I'll leave is just about parking, the biggest annoyance in Portugal in general, at least in my experience.
The apartment has some limited parking, hard to find spots and really hard to get in and out, no space to maneuver, you have to back out through the little street leading to it. There is nearby free parking, but it does get full quickly during the day.
Overall, we had a great experience, I definitely recommend and would come back! I just spend 3 weeks in the Algarve and Sintra was by far my favorite place.