I stayed here for 5 nights. This B&B is a few blocks north of the Termini train station, maybe a 15 minute walk. The footpaths on the way aren't in great condition so you might consider taking a taxi if you have heavy luggage.
I checked in in the afternoon (you will buzz in at the door on the street and say your name as checking in), the lady manning the reception desk didn't seem to speak any English but that wasn't an issue, a few gestures were enough to understand everything.
The room is basic but clean, functional and modern. I found the room a bit noisy, as you can hear the other guests coming and going, as well as other tenants in the building.
The bathroom unfortunately had an unpleasant damp smell most of the time. A second showerhead has been installed which I think the owners have meant to create a rainfall effect, however I just found it unhelpful as it has no water pressure for actual showering, and would occasionally drip cold water onto me while I was using the main showerhead.
Make sure you check your junkmail folder a couple of weeks before your arrival as they will request your estimated arrival time, to ensure someone's there to let you in.
There isn't much around the hotel area but at least you can walk to the Castro metro station and on to Termini and Rome's sights from there. Next time I come to Rome I will probably pay more for something nicer and in a better location, which no doubt will be expensive but I think worth it after this experience.