Wonderful experience for my daughter (11) and my sister. We had to reschedule due to the floods and they were very accommodating. The guide, Aiden, was very knowledgeable, personable, and helpful. It does require a lot of paddling, but our guide assisted when needed.
Xanterra was no help at all with schedule changes or questions. Not sure if you can book directly with Shurr, but I highly recommend doing that instead.