I didn't meet our host personally, but communication was excellent. Besides spanish, Carlos perfectly speaks english and german. The apartment is located at Torres de Serranos and is nicely decorated and fully equipped with everything we needed. Although it has no air-condition, a big (and quiet) fan is mounted which is needed for hot nights when noisy tourists don't allow to open the windows. During daytimes, one can open the doors of one of the seven (!) small balconies which allows a perfect 180 degree view on the place in front of the apartment and you don't need the fan.
I can fully recommend the apartment for those who like to stay at a central location in the city which is relatively quiet and stylish decorated. It's one of the better apartments available in Valencia!
Thanks, C. and O.