I've thrown both. I used them both on similar conditions, or when I wanted to play closer to the dry boards. I liked the Smokin' better because it was more predictable. The Radical was more "radical" for me.
There are going to be plenty of bowlers who like one or the other based on their individual game and what type of condition they bowled on. For playing the "friction area" of the lane, I can't think of a ball that has been better for me than the Smokin'.
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Lane Carter, Strike Zone Pro Shops - Salt Lake City, Utah