While there have been dozens of claims as to whose is best or cools the most? The simple fact is they all perform adequately and reduce the temperature down to safe operating levels. When choosing you should consider such things as do you use the top of the outdrive as a step? Do you have clearance issues with the back of the hull? Choose a unit with a water pick that is angled not 90 degree's to better perform under trim conditions, And lastly demand stainless steel to avoid corrosion problems.