This is a beautiful apartment, with lots of light, high ceilings and nicely furnished rooms. We choose it for the terrace and were not disappointed - it's huge, with comfy cushiony chairs and a large table for eating the delicious local food. In late September only the dining table was in the sun at lunchtime (handy), with everything else in dappled shade. We were fine with this, in fact when it was very hot it was a lovely breezy sanctuary. It overlooks the main road so isn't peaceful, but again we didn't mind this as it's excellent for watching the world of Trastevere go by.
The apartment sleeps four people easily, with the sofa in the TV room converting into a double bed and still leaving a large living room space. At time of writing the sofa isn't the most comfortable bed as it was extremely hard, but the other bed was fine.
The location is excellent - there are more excellent restaurants within a ten minute walk than you will have time to eat in - and Valentina was a wonderful host, leaving a practical selection of groceries, giving lots of restaurant recommendations and even helping us plan some day trips out of Rome. She responded to all questions quickly and was keen to help.