Very nice apartment in a great location, very close to the beach, only short walk to the old part of the city, bars and shops all around.
You can hear people walking around in the apartment above, and there is noise at night from the lift, which may bother you if you're a light sleeper.
The rental company were very responsive and great to deal with when we couldn't get the washing machine to work - you have to close the door very hard! If it's not closed fully, the machine doesn't work.
A really great place to stay though, we loved San Sebastian, the food is incredible!!