Futaba S3003/3004 question
 

what are the benefits of a ball bearing 3004? is it more efficient or what? and also how come it turns slower. isn't it like almost the same as the 3003?

You have just answered your own question :)

Yes,in short ballraced servos operate more efficiently and at a quicker speed than if they had bushings.

But that said,it depends on the motor in the servo and the gear layout that determines its speed and torque too.