Carlo's place is good for big groups. Its 2 minute walk to Tram station and takes 15 minutes to center and 15 minutes for airport and santa maria novella. It was also very clean.
A big problem for us was noise. There are garbage cans in front of apartment and garbage trucks would come all night and it was very hard to sleep. Windows lack insulation and sometimes you would feel that you were sleeping on road where even cars and scooters were disturbing our sleep.