The apartment is a perfect pied-a-terre to visit Sitges. The communication with the owner and its representatives was excellent and the check-in process was easy. A small issue with the internet was resolved within 2 hours. The place is immaculate with 4 bedrooms and ample living area. Note that there is a one-story walk-up.
No noise from adjoining units in the building. There is an occasional, low-rumbling sound from a nearby train, but it is almost not noticeable.
The location of the apartment is within a short walk of the center of the town and the beach, and far enough away to be completely quiet.
All around, it was excellent.