[Larry Lewis]

I feel that "best" is relative to what you value the most. For our team accuracy is the most important over distance, and speed. If you are going to take a shot make it count otherwise you spend more time chasing it down.

We did a two wheeled shooter in 2012 and actually found it to be much less accurate than the single wheel shooters. We thought that going with high speed motors on both sides of the ball would give us more range and having two wheels would make it more consistent but we were wrong. What we ultimately found out was that there is better energy transfer between the wheel and the ball when you give it a curved track to allow the mass to get up the wheel's spinning velocity. Because of this it was more consistent and seemed to go further even with less powerful motors. Ours just kinda burned out on the ball because we were taking something that is not moving at all and all of a sudden trying to get it up to full speed. This varied based on how well the wheels gripped the ball which changed as the wheels got dirty or the balls varied.

Echoing the previous comments I think execution is key and that any design can be successful as long as the time is put in to remove inefficiencies and variability.