It looks useful....IF your app is already a success and has massive downloads/reviews. For those who only get a review every few days(guessing 95% of apps), how does your service provide value?
EDIT: Responding to grandparent, I only get a review every few days, and I have less than 200 reviews. Nevertheless, this report did provide some interesting insight. Too soon to tell if I'll be able to translate it into a valuable decision. But I like that sensortower has been innovating on ways to analyze your data.