I stayed at Lorenzo's flat with 2 friends during the Fallas celebration week. The flat is amaizing, luxurious and situated in a very nice and lively neighborhood full of shops and restaurants.
We only had minor problems, but Lorenzo was a very helpful host. We had a problem connecting to the wifi, as the login credentials stated on the router were wrong. But I got in touch with Lorenzo and he gave me the correct ones right away. We also had difficulty unlocking the door of the flat. However we did manage to unlock it every time. The good thing is that there is a 24 hour concierge who is also able to unlock it if needed.
All in all- I would definitely recommend Lorenzo's flat if you're looking for a great place to stay in Valencia.