Well, I don't have experience with either, but I think you have to start on level ground. What I mean is the Action Max comes dull and the Terminator,despite being a solid particle, comes highly polished. Many people have trouble using a polished ball on the medium-heavy oil pattern for which both balls are designed.
So these are just cautions. Both balls are quite good for medium-heavy oil, as far as I know.
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"None are so blind as those who will not see."