We had an amazing time at Alessandra's apartment.
It's close to the city center and you have a metro stop right next to the house as well as a bus stop. The bus gives you a direct connection to the city center and with the metro you get directly to the beach.
5 minutes walking from the apartment there is a supermarket where you can get everything you need.
The apartment has literally everything you need. You wouldn't be missing anything in the kitchen or in the bathroom.
I highly recommend this apartment for a couple or any other constellation of 2 people that want to spend a nice vacation in Valencia.