I stayed in this apartment for 1 month, and it is in the perfect location - 15 minute walk to the old town, 20 minute walk to the arts and sciences museum, and 10 minutes by taxi to the beach.
The apartment has everything you could need, with very good WiFi. I worked a few days remotely from the apartment and had no issues at all.
The apartment is quiet and clean, with tonnes of bars, cafes and restaurants on your doorstep. There is also a Lidl only 3 minutes away.
Communication with Maria was speedy, and answered any questions I had very quickly.
Overall a brilliant apartment, and a great base to explore Valencia from. I would highly recommend staying here.