You'll always have the guy who insists his Seadooo is the fastest jet ski without any scientific data to back it up. The same goes for brand loyal owners of Kawasaki, Honda, Tigershark, Wet-Jet, Yamaha Waverunners, etc.
Measuring true speed across the water needs to be done using a radar gun. Relying on a rider to estimate speed just doesn't do it. Also, the idea of riding alongside a boat to measure speed using the boat's speedomoter is only as accurate as the boat's equipment.
What are your thoughts on the fastest jet ski ever built in large numbers?