This is definitely one of the best apartments I've rented on Airbnb.
Sergio is indeed a super host, very prompt to reply, friendly and helpful.
The apartment is new, and designed with good taste. It has everything you need for short and long stays (oven, bathroom essentials, etc.). Our favourite spot was the large balcony with the plants (please take care of them during your stay).
The location is also great, you are just a few minutes walk from the Ponte Lungo metro station or the Tuscolana train station from where you can take direct trains to beautiful places in the Lazio region, as well as Termini and Tiburitina for high speed connections to other cities father away in Italy. Another big plus for us was the multitude of supermarkets around.
If we'll visit Rome again anytime soon (hopefully), this apartment will certainly be our first choice!