The appartement is very central. Nearby is a metro station, a good supermarket and a fantastic pizza restaurant (with cheap dishes). Also the shopping street and many important places/buildings/museums of Naple are very close. We could also arrive all our destinations outside the city (for example Pompeii, Vesuv and the Coast of Baia) very fast.
But the appartement is very small and it's not much space for the general use (for example to eat in a sitting way). With two persons it's little difficult but possible and it's okay when you only want to sleep and take a shower there.
Even it was difficult with the small space it was a nice stay in Naples because the host is very friendly and helpful.