I've seen "O", "Zumanity", and "Corteo" so these are my basis of comparisons.
"O" is by far the most intricately designed, and most artistically complex of all the ones I've seen so far, and so well-executed.
I'd give "O" a 5, "Corteo" a 4, and "Zumanity" a 3.
We sat on the balcony, close to the front, so we were able to see the things they were doing inside the water as well as the choreography above the water.
I recommend this show to anyone going to vegas and has money to blow. get good seats.