I have a Robo Rule, Mean Machine, Arsenal Artillery, and a Machine on the way thanks to the Track Ball A Day Giveaway. Do you guys think I need all of them? Or do some of the balls overlap each other. I use my Mean Machine and Artillery the most but I don't know where the Machine would fit in. As far as the Robo Rule goes. I rarely find enough oil on the lanes to use it, usually it just burns up and looks more like a straight ball. What should I keep and what should I get rid of? Will the Machine be a good replacement for the Artillery? Is the Mean Machine as strong a heavy oil ball as the Robo? Any input from you guys would help. Thanks.