Is there any advantage to one over the other? I am overwhelmed with the choices of "outside" tour guides for going through the Vatican, Sistine Chapel and Basilica and wonder if it would be simpler to just book an official Vatican Tour Guide through the Vatican Museum website. I will have three teenagers with me and do not want to overwhelm them (ie bore them) by staying longer than three hours. Which kind of tour guide would be best for a two to three hour tour with simple explanations of what we will be seeing in the Vatican, etc.?
P.S. I hope this does come across as being prickly, but I would rather not receive unsolicited advice about what teenagers can handle. I know my children best and know how long they can last in museums/galleries:)