It's worked quite well for me. Overall hook isn't quite back to factory however the reaction is very close. The ball finishes much better now; it continues through the pins instead of deflecting and hitting weak.
I think the best way to restore a ball would be to use the Hook Again system in conjunction with a resurface. I still haven't gotten my ball resurfaced (and it's been 300+ games). My ball is pretty tracked up so by resurfacing (and using the Hook Again), hopefully an 'out of the box' reaction or something close to it, can be obtained.
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-Dino