The appartment was a bit disappointing at first, at least comparing to my expectations.
The photos are a bit "optimistic", the patio the windows are facing is not the one you want to admire, and overall the flat is in a bit worse shape than it seems from the photos.
The 4th floor means 75 stairs to climb.
After all these, the flat is fine. It is very clean and comfortable. The location is excellent. If you want to have a safe base to discover Rome it is a perfect choice.