The property is a combined 2/2 + 2/2, joined by a hallway, each size with its own AC units, which was perfect for our group. The photos are accurate, so we were happy with that.
The water pressure is good, but the water temperature can be tricky and unstable, depending on who is showering where. Sometimes, it would come out too hot, other times, it wouldn't get hot at all.
We did use the washer. Keep note that there is no dryer, so we had to hang the clothes on the provided clothes rack. Unfortunately, it was raining during our stay, so drying them outside was impossible.
The units are well stocked and there are double refrigerators, so if you have a lot of people with different tastes, it's a great set-up.
The location is literally perfect, with walking distance to everything. There is no parking close by, so we just parked the car in the garage and walked or took a taxi, if anything was far. Lots of restaurants to pick from. Even downstairs to the right, there's an awesome little tapas spot. And there are two markets on the same block.
As for the AC issue, the rear apartment's unit was not working for 2 of our 4 nights there. We were able to keep the doors between the apartments opened so that the air from one apartment pushed into the other, as best as possible. It wasn't great but acceptable. I reported the matter immediately to the staff. They did address it and provided us with a credit, which made us happy.
I'd recommend this rental for anyone visiting beautiful San Sebastian.