First thing I would like to address the preposterous review given by danielfelix. If the owner you mention is Fabio, then I have to question what YOU did to have him treat you badly? The biggest asset this place has is Fabio. Couldn't do enough for you, and always helpful with whatever request you asked for. He was anything but rude!

It's tough to rate this place, as it's not your usual hostel or B&B. It def has a lot going for it.
My wife and I stayed here in April, 2010 for 7 nights, split in two parts. Since we flew into and out of Rome for our Italy trip, we booked here for the start and end of our trip.
Good points
Great location near the Vatican and steps away from the metro.
Pretty good breakfast, fantastic coffee from his machine.
Communual fridge always stocked with yogurt, cheese and some snacks, and you can use it for your own stuff, just mark your name on it, since everyone else has access to the fridge.
Rooms were Ok and clean. First room was smaller and second room was a two bedroom.
Bad points
Washrooms are very small, but acceptable.
You can hear the click clack on the wood floors outside your room, so if there's a lot of activity, you are very aware of it.
There's one thing that really threw me for a loop, and maybe we should have known better. Our rooms had windows that opened up to a courtyard. Nothing much to look at, but allowed air into your room. Having stayed here already 3 nights on the first leg, we nevered heard any sounds coming from the courtyard of our neighbors. The latter stay in a different room, we had the windows open, and would be chatting, when we heard a voice that sounded as if the person was in our room. She kindly asked us to keep it down, since it was obviously just as loud in her room. We subsequently kept the windows closed, but made it more stuffy. Not really a big deal for us, but I only mention this, since someone who may like to retire early may find themselves in a position where your neighbors are not as understanding, or maybe roudy, could really impact your stay. We had pretty awsome people staying, so never really had much of a problem. We were probably the roudiest, lol!
Ultimately, this was a great value for a stay in this location.