Rome is great, we continue to go there and always love it.  The only thing we did not like was the Trambus Open bus. The idea is good, they take you from landmark to landmark for a fixed price per person ( between 13 and 25 euros.)  You get out at any landmark, stay as long as you like and hope in another bus to cover other landmarks. The problem is that the bus is full most of the time so you cannot get on and you have to wait or just give up and take a taxi. For a group of three to four people it becomes expensive. We ended up taking a taxi, paid by the hour and got much more for our money.