Maybe it's just because I'm so used to them, but...
Gents, these are Glo-Balls. They have a plastic coating. Shoot a plastic anything at targets at a high rate of speed, and you're going to get dents and whatnot. It's like the dimpling argument, "oh no, the playfield is dimpled! Why doesn't the _______ old game I get do this?" Well, it did until it got so dimpled you didn't notice it any more.
Below is a picture of my Glo-Balls. If I hold them up and look at them carefully, I notice that none of the balls are perfectly round, they have these little flat areas all over. They have little edges that collect that black gunk on them. They are lighter than a steel ball by a considerable amount.
And they work great for what they do. My VND has had more than 3000 plays since I got it, including being at shows with the Glo-Balls in, and no one has once told me that the balls don't roll quite right. I bought (indirectly) a set of actual glowing balls, and I expect to install them in my VND sometime soon (all my VND boards are currently in SST). The wear pattern that you're showing me after 300 or so games looks outstanding to me, and I'm quite excited to know that I'll be able to save these nasty old relics and play with balls that actually react to the light properly now.
Now, if only someone can fix the cool playfield mylar appearing glowing effects in the future and repro the raccoons, I'd be able to make my VND nicer than new
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