We spent 6 nights, 7 days in Rome (in this apartment), and I think it is located in the best part of town! Every day we would eat lunch and dinner at a different place, and everything was within a 10 minute walk. The Vatican, 15 minutes walk. The Pantheon, 10 minutes walk. Very hip bars just blocks away. The street itself is relatively quite and family friendly.
Inside, you could not ask for anything more; everything you need is there, and plenty of space (have to love the AC in the middle of a June summer in Rome).
Communication with Federico was very easy, and he was very helpful in setting up pick-up services to and from the airport. As this was our first AirBNB stay, I was very happy with the whole experience, and hope that all of the following are as great as this.