This was my second-best tour with JY after Australia. I had been to the Grand Canyon before, but it never fails to amaze. However, the other sights you will see are equally amazing, all being very different. Rather disappointed with Monument Valley - no John Wayne riding through! I jest, amazing sight.
I agree with the comments re the excursions to Salt Lake City (nothing there apart from the Mormon temple) and Las Vegas by night. I have been to LV twice with JY on different tours and the first time the traffic was so bad that we spent most of the time trying to find somewhere to park. Much better to walk and take in all of the displays and lights.
Holiday so good that is likely to be the only that I too will repeat!