The apartment is super convenient, with lots of plugs, lights, and other nice little touches to make it pleasant. The design is modern and fun, and the location was perfect for us. It's very close to the Vatican, and there are lots of restaurants in the area (we returned to the neighborhood every evening for dinner). It's a bit of a walk to other tourist sites, but that just gives you more opportunity to explore all over the city on your way to check off your must-see locations. A great neighborhood for a more relaxed vibe.
Only item to make sure you note: there are about 60 steps up to the apartment, with no elevator.