We stayed with 2 persons at the appartment for 4 nights. The appartment was great and exactly as shown in the pictures. Everything you need was there in the appartment (fridge, dishwasher, washing machine, etc. ) and everythins was clean. The bed was great and it was comfortable to sleep. Also the Wifi worked excellent which was important to us because we did also work from there.
We ran in some minor issues at the check-in as the appartment is locked with an electronic code and for whatever reason it took us multiple tries at the first day to unlock the appartment even as we used the right code. The hosts (which is a professional agency) responded very vast when we contacted them via the AirBnB app and explained us the backup plan which was not needed anyhow as the issue dissapeared from day 2 onwards.
Regarding the location of the appartment we would recommend to do some research what you want to do in Valencia and then decide wether the location suits you. To the beach it is a 15 minute walk, into the city center you need to take public transportation (recommend bus No 4 which departs approx. 150m away from the appartment) and to the museum district it is also a 15 minute walk. So basically everything is reachable within 15-20 minutes but you are not on location. The direct area offers supermarkets and smaller quick service restaurants.
So the appartment as such I would definatley recommend but at the same time I would also recommend to check if the area suits you.