Very clean apartment and even though we didn't speak the same language, we were able to communicate easy.
The check-in and check-out was an easy process. We could even leave our luggage a bit longer, which was great considering our late flight.
The building can be quite noisy as you can hear the other tenants doors opening and closing and a dog barking on the level above. But none of that mattered given the great view and all the nice little restaurants within walking distance.
What we especially liked was the cleanliness of the bathroom and apartment altogether. The only thing I would say is missing is a long mirror.
Within 3 min you can take the metro and from the airport it was a short 50 min with one transfer. Just take metro 3 or 5 from the airport, transfer at Beniclamet onto the 4 to Dr Lluch and get off at Las Arenas. It will cost you around 2/3 euros. Don't get the tourist card, but a regular metro card which you can recharge. A single ride in Valencia costs 1,50 and if you travel with a group, just get 1 card and use it as many times as needed, scan 2 times if you are with 2 people.
I would also recommend to eat in the Centre area, try Los Guacamoles or Bar Richard