I agree with this:
"While it was anticipated that rallies with the green ball would be longer they were actually almost the same, 5.25 shots per rally vs 5.35 at yellow. The reason for the slightly longer rallies at yellow was the number of long “moon” ball rallies which increased the average.
I know I'm alone on this board in not having a genetic freak for a child. For my 8y/o, orange and green balls are a godsend.
I do wish the USTA would revisit red balls as a 23" racquet with red balls is ridiculous for a normal sized 8 y/o. It's almost racquetball. Maybe red balls could be 7U.