The place is in the small chinatown-like neighborhood, lots of Asian restaurants and shops in the area. It is 15 minutes walk from Roma Termini and probably 25-30 minutes to Colosseum. There's the nice supermarket on the other side of the street, and that famous gelateria right across the entrance.
While the neighborhood might seem sketchy at evening ( due to the vicinity of the station ) - we felt pretty safe in the area, traveling with the kid. Still locals don't recommend to stroll through the side streets at night alone.
The apartment is spacious, with amazingly high ceilings ( I wonder if those are close to 15-20 feet ), nice bedrooms and the kitchen pretty comfortable for 5 people to have a dinner. We found everything we needed, with the great surprise of a pack of chilled water in the fridge ( more than enough to make you happy after walking in something that feels like 100F outside). The bathroom is new and nice, the beds are good and there is plenty of kitchenware / silverware in the kitchen.
The only thing that tinted the otherwise perfect experience was that noice from the street. These trams are like rocket jets, and they start early, mind you. So either you sleep really well, or you must get some good noice cancelation earplugs.