Location, location, location: I'd highly recommend staying at Francesco's place if this is your first visit to Rome. The apartment is a two minute walk from one of the most beautiful piazzas in all the city, Piazza Navona. The apartment is also within a 20 minute walk of the Spanish Steps, Trevi Fountain, and the Pantheon, and about half an hour to the Colosseum.
The apartment itself is gorgeous and well-designed. The apartments high ceilings and corner location give the space a welcoming sense of openness.