The apartment is amazing: it is old but well renovated, with a very authentic atmosphere. I actually chose it because of the authentic vibe and historical house. The location is perfect, it is right in the middle of the old city center. There is a small supermarket across the street and around 7-10 minutes till the central market which is open between 7:30 am- 3 pm where you can buy food and cook meal at home. The kitchen has all the things required for cooking.
The only drawback for me was that in November the temperature outside, especially during the nights, is cold, so the apartment can become also relatively cold. If you plan to stay the whole day in the apartment, it can be chilly. Juan is a very nice and responsive host, he adjusted the heating regime but it was still a bit cold for me. I suggest taking a sweater and warm socks to feel comfortable if you are traveling in the late autumn (it is general advice for Valencia in autumn)