I found it not quite as bad as the other reviewer reported. The room I had was comfortable enough, with A/C, a TV, and a sink. (Note: the only bathroom is shared among 7 people!) Not spotless, but I wouldn't call it dirty. It is in the absolute worst part of town, but it is extremely close to the train and metro station, very convenient. Breakfast is a pre-packaged croissant and (good, as is all Italian) coffee. It was going as a solid 2-star rating until...
On my last night there just before midnight a gruff old man started banging on my door shouting what apparently was the only non-Italian he knew, "Pay! Pay now!" I hadn't seen anyone like him around before, and because of the seedy neighborhood I worried that he might have been a shady character who had gotten inside the main door and was trying a ploy to get me to open my door, since this was pretty unusual behavior for a legitimate innkeeper. I tried to communicate in a couple languages (not Italian) and all I could get was "Pay now" interspersed with salvos of angry Italian. He pretended to call the police on the phone two different times, and after a long while he eventually gave up. The fellow tending shop in the morning said that it probably had indeed been the night attendant and apologized several times for that interchange, but the whole experience still dropped my assessment of the lodging a notch.
BTW, their web site makes it look like a family operation; I never saw any of them, and where I stayed was apparently another B&B in the same building (Antonietta's House) they were either reselling or had bought.
In all, you get what you pay for, and I paid for the cheapest accommodation I could find (70 Euros/night) within walking distance of historical Roma. I'd say it rates a 1.5 / 5.0, because it could have been dirtier and I wasn't actually robbed.