My son summed up the situation well about the Roma Pass, which probably isn’t worth the $25 Euros to most if they can avoid the Colosseum lines, which I think you can do if you buy that ticket as a combo ticket at the Palatine Hill Entrance to the Ancient Rome area.
It’s important you see the Forum and Palatine Hill as well as the Colosseum, and with an audio tour of these three you’ll spend perhaps a half to full day in this area for about half the cost of the Roma Pass. The Vatican is NOT included in the Pass so our 2.5 Rome days involved only one where we used the Pass. We DID get to skip a huge line at Colosseum but I think we could have done that with the combo ticket you get at Palatine Hill or Forum area where lines are likely to be much shorter.
“We decided to buy the ‘Roma Pass’ which lets you skip lines, get into the Colosseum and stuff, and ride public transportation for free. We picked up the passes in the station for 25 euro each. The kit it’s contained within is well put together, it contains a little map and some tourist information. However, in hindsight we’ve determined it wasn’t worth the cost in our case – mainly since the metro here is cheap, only 1 euro a ticket.”