It was ok for the price but there were some negatives that I'm gonna list in case it's important for someone:
-the walls were thin so a lot could be heard, especially in the bathroom
-fridge (and consequently the whole kitchen) smelled terribly
-it was so cold we had to wear winter jackets inside even with the heating working on maximum setting. However, we were unlucky to get the coldest days Naples had seen in a while so it won't be an issue for most guests
-It was also really windy and the windows/doors were quite noisy which was a bit disruptive for sleeping
-even though this place lists breakfast among the services provided (and as such passes through a search filter), it's actually just a voucher for one 2€ discount/person in a near bar. Roberto insisted it's good for 1 coffee and croissant but they asked €3,5 for those
However, there are always some negatives in this price category. Despite all this, it was worth the price for us and we would stay there again