I think this is one of the best places for stay in San Sebastián that you can find on Airbnb, and it has great price/value correlation.
Our room had I suppose everything you may need for spending few days of your travel there: small fridge, desk and table lapm, bathroom, good bed. Room has enough space for two. I would also like to mention that room and common areas were really really clean.
Another thing that makes this place outstanding is the location. It is really close to bus station, and to the different touristic places, shops, bars.
Room also was light, quiet and quite warm.
And of course Jon is an amazing host, he was always there to help with any problem, had great recommendations about the city, he speaks English really well, and he was simply friedly and attentive.
I would totally recommend this place.