Indeed a charming place. It is located in a passage that goes up the hill from trastevere to Giancolo: beautiful, quite and full of plants. In his apartment Guido provides everything for you to feel at home (cooking stuff, basic breakfast staff, toiletries...). the appartment is clean, modern and nicely decorated.
I did not have the change to meet Guido but Marco, a friend of his. A very nice guy, as Guido seems to be also by the messages that we exchanged. I can only recommend this place!