We had a great time at the apartment and I'll definitely recommend it!
We took the metro from the airport to Colon (25minutes) and directly found the apartment (150m). The situation of the apartment in the city center is excellent because there are many facilities nearby that bring you to other parts of the city (Bus, Metro and citybike). Also, the supermarket is 50meter away..
The apartment is very spacious with a very nice living, three bedrooms (4 single beds, 1 double) and two bathrooms. The kitchen is well equipped so you can make whatever you want. It is quiet outside so you can enjoy your sleep. The communication with the owner was good (very fast responding by WhatsApp). We had such a good time in Valencia!