Awesome location. Our family of four was very comfortable, and we could walk to the Vatican, pantheon, and campo do Fiori. There are tons of great restaurants very close by, which we took full advantage of!
Federico was a great host, and arranged car services for us on several occasions.
The apartment itself was perfect for us, my two boys had their own rooms, which eliminated a lot of arguments. The AC was not quite as strong as we are used to in the US, but it felt great after walking around in the summer heat.