The location is unbeatable - it's a great, atmospheric neighbourhood and a huge amount of the city can be seen on foot. Communication with Daniele was extremely good and I was grateful that he could accommodate me at very short notice. The place was very quiet, the wi-fi is fast and reliable, and the heating worked great. The guidebooks are a nice touch.
Note though that it the place is very small, with almost zero natural light, and the curtains do not close all the way, which could be an issue given that the small outdoor area in front of the apartment is not strictly private (other people in the block can conceivably walk right up to the glass doors). The bed is large and comfortable, but very soft. There was also a faint smell of damp about the place. None of this is a deal-breaker though if all you're really using the place for is a bed while you explore Rome.