Great flat in a very nice location. If you have kids like us, the vicinity to the huge riverbed park with playgrounds and skateparks etc is perfect, while still being very central and close to the cozy parts of the old town.
Check-in (note 1): to check-in you must check your regular mail inbox - not the Airbnb one - for a special online check-in procedure. This was not communicated in advance - a point to improve - but upon arrival when the issue arrived the host was fast at solving it for us.
Check-in (note 2): The location of the key pickup is different from the flat. But it's nearby, I think a 6 minutes walk, and would be no issue in case you follow note 1 above.
Apart from our issue above, the stay was really good. Comfy living room, enough kitchen utensils, a toaster, etc, and if you need space for kids like us I think it must be one of the better places to stay while in Valencia.