Enjoyed every day of the tour. Our guide (Steve O.) was excellent - considerate of everyone and very knowledgeable (~ 30 years experience at various jobs in Yellowstone). For me the highlight of the tour was the Day 3 Geyser walk. When we gathered outside the Lodge at 9 am the outside thermometer showed -30C and everyone agreed that it got even colder
...read more towards the end of the walk when the path went down a slight slope to a lower lying area - an easy walk and a good test of one's "layers".