I was apprehensive about staying at a B&B but I really liked this one. Remember, you are staying in a room in somebody's home, so think of a house on a quiet street, not a fancy hotel. It's only a short walk away from the huge Termini station. Make sure you take the correct exit (I think it's Via Giolitti).
Maki, the owner, welcomed us upon arrival, gave us a city map highlighting the main tourist attractions, bus/metro routes and grocery stores, and lent us an emergency cell phone. We had a computer and free Internet in our room, which came in very handy for the train schedules.
We told her it was our honeymoon and she gave us the room with a private bathroom. It was nice to not have to share!
Breakfast foods like cereal, croissants, cookies and brioches are in containers in the main hallway at all hours so you don't have to worry about schedules.
Air conditioning is an extra 5 euros per day but we stayed in September so didn't need it. Can't say if it's loud. Maki's English is great, and she is Japanese, so she'd be able to help you out in case of an Italian language barrier.
The price for the area cannot be beat.
