Had an absoloutly perfect stay at Andrea's Place (The Great Beauty). The location is spot on and the main reason we picked it, you couldn't get any closer to the colosseum and the views are stunning.
Within walking distance of all the major attractions (only 25 minute slow walk to Spanish Steps) however we took a bus ride to the vatican but it could easily be walked as like everywhere in Rome there are always great places to stop off at on the way to either eat, drink or just gaze at the surroundings.
The apartment itself was very clean, very spacious and had all the amenities you would need. Amazing restaurants and bars right beneath the apartment (highly recommend La Taverna Dei Quantana for authentic Italian/Roman food).
Andrea as a host was amazing too and the communication was great, arranging taxis, check-in etc.
Overall we would definatly stay again and if your looking for somewhere to stay for your break away in Rome this is the place.
Grazia Andrea!