We had a three wheel machine for a while and it used a leather ball. The girls said that the balls stung their hands. That machine broke. We were then forced to use a Jugs machine and went with a dimpled ball. It was a Jugs 12 inch sting free dimpled machine ball. They cost about $69-79 per dozen and they don't seem to hurt the girls hands. We did break a bat but it was 3 years old. These balls for the most part fly true and give a repeatable pitch. I have noticed that sometimes the machine will walk a little bit and then the balls have a tendency to ride inside on the batter.
I don't really like to use the machine, but it is the only way that we can simulate game speed.
Does anybody wash the balls. We have some balls that are about a year or so old and I notice that they don't travel as true as the newer ones and even the newer ones have collected a lot dust and dirt from the balcony floor and then that dirt ends up on the wheel and I think that causes the ball to slip one way or another. I'm thinking if I wash the balls and get the dirt off the balls and out of the grooves that they would fly truer. I seem to be the only one that is worried about this.