The flat is for great, but you need to be happy about climbing over 50 steps to reach it on the 4th floor (well 3rd, really, because they call the ground floor as floor 1 out there). Highly recommend this location for ease of access to central Rome sights. Get a €24/person 7-day bus/tram/metro/metropolitan train network ticket: great value if you do decide not to walk to all the tourist spots.