We (and our 10 year old son) stayed in Sergio's apartment for almost 3 weeks. Sergio is a very nice person, he brought a desk when we needed a place to work in the apartment. The seaside in the area is really enjoyable. There are many restaurants and bus stops and it is very easy to get to the center of Valencia.
This apartment allows you to go back to the '90s, especially when you are in the kitchen, without a dishwasher. You need to know that you will pay for a fairly low standard. The air conditioning is very old and only affects one room. When you sleep in the white bedroom, about 12m away from the air conditioning, you have to open the window at night, but beware - there are also mosquitoes outside.
The first impression was not very good but we got used to it and had a great time in Valencia.