Overall, good but not great.
The pros:
Location - walkable to the beach and to the metro for city centre. One day we even walked all the way from the apartment to the centre.
Facilities - inside, the apartment is modern and well appointed. It has everything most guests would need.
Situation - thankfully on the 1st floor (out of 9), as lift can be a little slow. So stairs are an option.
The cons:
Location - it has a little park area with a playground directly opposite, which comes alive at night. Valencians seem to be nocturnal and those in this park are very loud and inconsiderate, often until 4am!
Bugs - we were bitten by mosquitoes (our baby especially). You get a whiff of sewage often in this hot city, but it was uncomfortably close to this apartment.
The factors that disturbed our stay were outside of the host's control, but forewarned about the nightly noise outside the apartment, you can decide if it's suitable for you. It wasn't for us due to our baby and the light sleepers among our party. Be sure to bring your own mosquito repellents too.
Otherwise, a good apartment.