This apartment (booked for 2 adults and 2 children) was well-priced for the dates that we booked (first of September). It is also in an ideal location, only a 10 minute walk to the main train station and most of the major sights.
From previous posts we knew that we would need to pay with cash, up-front (we did not know that we would be hit with an additional Rome hotel tax of 2 euros/person/night, for a total of 16 additional euros). We also knew that the apartment was hard to locate, but we had used google maps to provide directions from the train station. The taxi driver had no problem finding the place, once we showed him how Via Modena was spelled and he taught me the correct pronunciation.
The owner was out of town, so we were checked-in by an assistant. It takes many keys to stay in this apartment. There is a key to open the front door, another key for the elevator (we only used this for luggage), another key for the apartment door, and keys for each bedroom.
There are three "bedrooms" (1, 2, 3) associated with the apartment. Bedroom 1 does not have a bathroom, so it can only be used in conjunction with bedrooms 2 or 3.
One problem that we discovered was a lack of hot water, but we did not want to call the owner late at night. Instead, we waited until the morning and she guided us through the problem by phone -- basically, the hot water unit (an instant-on Rinnai system) is in the bathroom associated with bedroom 3, and there is a switch outside the bathroom that must be turned on to provide power to the unit. If another party was staying in bedroom 3, we might not have had access to turn on the switch.
Our kids loved staying in bedroom 2, which has a bathroom, couch and TV downstairs, and a spiral staircase up to the loft where the two double beds (next to each other to form a regular size bed) are located. We stayed in bedroom 1 (which did not have a bathroom), but used the bathroom in bedroom 3 (where we were originally supposed to stay, but the air conditioner needed to be repaired).
A concern, in addition to the hot water issue, is that the wiring in bedroom 1 is definitely not up to code. All power is supplied from one outlet, with two extension cords in series to supply power for a TV, refrigerator, reading lights, and a hot water pot for coffee/tea (this did not work anyway).
Overall, I would recommend this apartment as long as you are adaptable and can pay cash up-front. I would certainly confirm with the owner that you are the only party staying in the apartment.