I've noticed a very minimal amount of shimmer. Not much at all.
It is there. It is very subtle though as I can see it on my sand bed which is 30" deep and the SKY's are mounted 8" above the water line.
After the change my wife passed by. Hey, I see you removed the swimming pool from your den...
Kessil is like scuba diving at high noon over a reef crest at 30'. Great lights for a reason. SKY does have shimmer but it is not as pronounced. It is soft and in unexpected places that you may not see before. Is it Kessil shimmer though? No and that question should be on the prospected buys pro/con check list.
Edit: to clarify I am not saying you are wrong I was trying to paint the picture that it is there just not loud and proud if that makes sense. Sorry if it read like I was saying you are wrong. Sorry!