People usually look at the current assumptions in the illustration and pick the product with the highest rate. Here is why this could be a mistake.
Whole life is a permanent life product that is meant to be owned for decades. Current assumption of dividend interest rate just shows you the current rate, and the illustration assumes the current rate would last in the next several decades.
Unfortunately, dividend interest rates do change over time. A company with the best current rate might have a low rate in the past and/or future. What a better way to compare is to look back a few decades, and apply the average dividend interest rate and determine which company has the best rate on average over a long period of time.