I did a lot of research to decide which Hop on Hop Off to use in Rome. None of the companies seemed to snare the best reviews, so I decided to go with the Big Bus. Granted, it was mid-March and not mid July (and starting to get very crowded), but everything was great. Have your bar code ready for scanning when you board, and they'll give you a ticket to use for the rest of your time. A lot of people just aren't prepared to board, and that ties things up. Many of the complaints refer to having to walk far to the sites. It is what it is. All the buses stop at the same places. Our ticket was good for three bus lines, so we didn't always have to wait for the Big Bus. That was nice. Another common complaint was the buses sitting at a stop for a long period of time. I found that to be true for just some of the stops (#6 Vatican City, #1 Rail Terminal and #3 Colosseum...big stops for tourists). The rest of the time they would stop for less than 5 minutes. If in doubt, go with the Big Bus.