I've been many times to Valencia, but this is one of the best places to stay in city, right in the middle of the action, within the city center. The building is recently renovated and the apartment itself is sparkling clean and brand new - from furniture, appliances to towels and bed linen, everything is in perfect condition and exactly like the pictures on Airbnb.
I've stayed at Maria and Juan's place for a month and it was a great experience - they are both really nice and helpful and you can rely on them for anything. They've meet me at the apartment when I've arrived and it was already provisioned with everything I needed for my stay.
Nearby, you have a lot of attractions (historical center), many public transport connections (such as Metro, tourist buses and city buses) and supermarkets (El Corte Ingles, Carrefour Express and Mercadona), within easy walking distance.
I'd highly recommend this apartment for visiting Valencia and getting around to almost anywhere - within 20-30 minutes, Xativa - Marina Reial, you're at the beach and within 5 minutes you can reach the amazing flat riverbed park of Turia and head down, maybe 30-40 min walk, it towards the City of Arts and Sciences.
If you don't like walking or running trough Turia, there are over 10 bus lines all around the Apartment that can get you to anywhere, or take the Metro from Xativa, which connects to as far as the Airport.
Keep in mind that travelling by car it will be considerably harder to park. There are just a few parkings inside the center and quite expensive. Yet in Valencia, there's absolutely no need for a car when you can walk or rent a bike (Valebisi is one of the best options) to move around.