The location is amazing! I would give it more than five stars, if it were possible. Many good restaurants, bars, and shops right in the neighborhood, as well as a nice playground and ice cream shop one block away. I could also go out the front door and be paddling out to the surf within five minutes. It was the perfect place for my wife and I to stay with our nearly two-year-old daughter while in San Sebastian.
Carolina is a great host. She and her husband were very responsive and answered any questions we had. They also provided a high chair and pack n play for our daughter (very nice to not have to lug that along!).
The apartment is nice and quiet at night, though the only drawback during our stay was that there was construction happening in the building, as well as on the exterior of the building across the street. It wasn't bad most days, but there were a few days when it was pretty loud. That said, if we hadn't been in the apartment in the afternoons for our daughter's nap, we may not have really noticed the construction noise.
Overall, I would highly recommend Carolina's place to anyone visiting San Sebastian. The location is perfect, the view is amazing, it's clean and comfortable, and Carolina is a wonderful host.