We had a wonderful time staying at Sergio's - he really is a model host, so accommodating and friendly! He even let us drop off our bags in the morning so we were free to explore Rome all day, and didn't judge us when we couldn't find the towels he had left out for us. (:
The location is excellent - very close to bus routes that take you right into the city, and near metro stops as well. There are also lots of interesting things to do around there, and restaurants and cafes right outside.
The shower is on the small side, which didn't really trouble us, but could be a problem for a bigger person. The room on the other hand is massive with plenty of room to spread out and spend a longer time. We felt super comfortable - in spite Rome trying to cook us alive, we wish we could have stayed longer!