Bill Gately and his team from
Bonneville Performance run the 270º motors. I am also pretty sure that all the Yammer guys also convert their bikes to run at 270º to compete as well. There are kits available for many bikes to change the stroke just for this reason.
270º motors grab the road better (torque)
360º goes a little faster in the long run (HP)
But, the difference in HP is also minimal. I believe it is about 2hp between our motors and the Bonnie motors.