The apartment was as described. 2 main bedrooms with twin beds, a lounge / dining room, small kitchen (but we didn't cook anything anyway), and a small wet room / bathroom. It's by no means luxurious but extremely functional.
I wondered quite how the breakfast would work as it didn't explain that but it was a coffee maker, tea bags, fresh milk, pre-packed croissants, tarts, and biscuits, and a loaf of bread and toaster with some jam - all more than adequate for the start to the day sightseeing.
It's about 1/2 hour walk to the colosseum and Vatican in either direction. There are lots of bars and restaurants within a 5 minute walk if you don't want to too far.
The flights of stairs to the apartment are hard work, especially after a long day's walking but that may show how unfit I am. I certainly wouldn't want to do them with small children, heavy cases (we only had hand luggage), or elderly relatives.
All in all I would consider using the apartment again if I came back.