First, the location of the apartment is perfect, 5 minutes from Termini Station and at 5 minutes to Piazza della Republica. Also, you are at 15-20 minutes walking from the main monuments, and we have only had to take public transport to go to the Vatican City.
Secondly, the host wait for us to give us the key even though we arrived very late (midnight) and was very kind with us. She responded our enquiries very fast and on a helpful way.
Also, she arranged a place to leave our luggage for 5 hours so we could enjoy the morning before we left Rome.
And lastly, regarding the apartment, it was quite big (we were only a couple), very clean and modern furniture.