We caught the wrong bus and were running late so it was nice to find that I had actually booked a PRIVATE tour and that our guide was still waiting for us! I had forgotten that I had booked a private tour. Our guide was excellent. An easy going 'go with the flow' kind of person which made the experience so much better since the place was swarming with tourists.
They locked the door between the Sistine Chapel and St Peter's while we were in the Sistine Chapel due to some procession in St Peter's. We were happy to wait as we will probably never get back to Rome and our guide used that time to show us some pictures and explain a few extra things to us.
She was open to suggestions of anything we particularly wanted to see and welcomed questions.
The day before our tour we went past the Vatican while on the 'hop on hop off bus' and saw the queues. I'm so glad I booked before we left Australia.