This place was exactly as described. Yes, there are stairs, but it’s not any more extreme than what we had in Florence or Lisbon (these steps are a tad steeper in spots but my kids managed them 2-3 times per day).
It was really hot when we were in Naples and the AC was helpful. It was not the most powerful AC in the world, but it was good enough and in the living room and both bedrooms. The beds were comfortable and the apartment is in close walking distance to a number of attractions.
We did not use the kitchen or the TV so I cannot speak to those. Overall, this place was great for our two night stay.