We booked a tour of the Vatican Museum and St Peter's through Viator, it was very costly and marketed as a semi-private tour. We found it confusing to find the meet up point and as a result the group left without us, even though we were in the mmediate vicinity at the tour start time and being 4 of us we would have made up at least half the group! Request for refund or any other form of compensation was flatly refused, but from the string of bad reviews I've seen, I'm no longer surprised. Agree with others who recommend just booking directly with a reputable tour company.