The criteria is impact on motorcycling in general. With that said, there is no doubt the cub should be 1. The duc at 2 is a bit confusing. It is a landmark bike wrt design, but not it's impact on motorcycling. the 750 should be right up there, likely 2. yes it is boring. Even to this day, some 36 years after it was made, my 750 amazes me with it's fit and function compared to all my other bikes, both old and new. It starts right off and just works. Ye's it's boring in stock form. Brakes are adequate, sound is uninspiring, comfort is ok. But as a UJM, little else can match it's capability and durability. I can see why it's at or close to the top.