I have stayed over Sergio's place for two days during my stay in Rome in december 2015. On the first day he explained me very well everything I needed to know to stay at his place.
I think he is a great and reliable host, who made my stay easier in Rome. While I was slightly late at our meeting on the first day I could reached him by phone to let him know. He also wrote me down all the instructions to use public transportations (buses, metro, and to get back to Airport), lent me a city map and shared wise advices about places to eat out. His flat is clean and well furnished.
I would recommand to stay at his place without any doubt.