We had mixed results with the The Tour Guy too and wouldn't use them again unless there were not alternative options. One of our tours was great and we loved the tour guides on all of them. But, we changed the colosseum tour date and even though they confirmed the change, I had a hunch to double check, which I did, and was promised they had us down for the right date and time. If there is one thing I have learned when traveling, it is that when you make changes to anything scheduled, it gets screwed up by the vendor. For some reason, change is hard for most of them.
Or course, we show up at the double-confirmed day and time and they say they didn't have us in the group because they had us booked on the old date, and "no," there wasn't room in this group, but they could fit us in three hours later that day. Than meant we went from purposely touring prior to the heat of the day to doing it mid-day, when it was very difficult for a family member with health issues, which meant we had to bow out early and completely miss the Forum, which I was looking forward to. I understand mix-ups, but when I reach out to confirm everything is set, giving you a second chance to make sure you haven't messed up, and you just lie and say it is all correct, there is no excuse.
Similarly, we paid for early entry to the Vatican, where were promised to be let in an hour before the rest of the tour groups. Our tour ended up entering long after dozens of other groups and wasn't early entry at all. We were lucky that it was soon after Rome was opening after the pandemic and it wasn't very busy anyway.
That said, all the tour guides were great, so I at least appreciated that they found qualified local guides. I would use them again in a pinch.
When we go back to Europe though, I am going to do more transportation and self-guided tours (which include front of the line entry but no guide once in), because I found we like to explore at our own pace, and for most of the important sights, Rick Steve's has exceptional audio tours that included more detail than even the local guides provided.
The one tour I liked the most was the half-day tour where the guide just took us around the city. It was fun because she took us to several places we wouldn't have known about, and knew the great stops for gelato and snacks. It was one of our most enjoyable tours. It was also nice to be able to just chat with a local and get a better feel for the city to start our four days there. I might do that to start our stay at any major Europe city from now on.