We stayed at the Rome Marriott Park Hotel when they first opened their doors and again 18 months later. It was a wonderful stay. It is not at all in the center of Rome, but outside, and this was a great factor for us so that we could unwind a bit each night. The spa was amazing as was the restaurant. The hotel staff were lovely and they have a shuttle that will both drop you off AND pick you up later in the day/night which is a help and cost savings. When we return we will stay here again. As a side note we have also stayed at the Courtyard Rome airport and were disappointed. IT was difficult to find and was too far from the city. The staff there were helpful in arranging transport but it was incredibly expensive. Enjoy your travel there!
Only stayed at Grand Flora using points as cost/night is quite high! If you're a non-smoker, there's only one floor here that can accommodate your preference. My Marriott status granted us free, bountiful, buffet breakfast and we ate late; therefore, we needed no lunch elsewhere. *Warning - if you have a cup of coffee in the lounge at night expect a $20 bill! Enjoyed our stay as hotel is central to many places you'll probably want to visit, most in walking distance.
To really enjoy Rome I would like to suggest that you stay in the Flora, it is conveniently located to see and have fun in Rome. The other properties are not in Rome, they are truly middle of nowhere.