This was the highlight of our trip to Rome. The guide was well informed and we never would have known half of what we were looking at. The lines were 2 to 3 hours long off season and we were in in 20 minutes. The only down side was the ending at the gift shop. Very rude staff and prices 3 times what they here everywhere around the Vatican. Take the tour skip the gift shop. The peace cross of JP II can be found for 15 euro all around not 45 as in the shop.
The tour guide in Siena was great. She was very personable and extremely knowledgeable. We would not have gotten nearly as much from the trip without the tour. We will recommend the tours to all our friends.