To answer your original question -
Of the 3 products you mentioned, I've only used Ebonite Factory Finish on a couple of balls.
I first used it on a Savage Flip that I wanted to return to factory finish. I originally took it down to 800 grit to ease a problem with over/under. Gave it a complete resurface (starting at 320), ending at 800 grit before applying the polish. The ball never did return back to the major flip reaction it had out of box. Ball still rolled very well, but never really jumped off the dry like before. That could be attributed to the fact that my release changed.
Used it one a Velocity that I had dulled down. Didn't notice any loss of reaction after using Factory Finish (compared to the reaction out of box).
Also used it on my wife's Trooper - she throws a straight ball and just wanted it shined up.
I'd have to agree with Shelley, that as long as you match up the final grit, there probably isn't much difference between any of the products.
Sounds like you've done the research:
Storm Reacta Shine - 1500 grit
Storm Xtra Shine - 3500 grit
Ebo Factory Finish - 1000-1200 grit (estimate)
Other things to look at - you can still pick up the Track products from several places on-line:
Track Clean N Smooth - 1500 grit
Track Clean N Sheen - take 320 up to 1000 grit
Track Magic Shine - restore factory compound polish
Bowlingindex.com had some nice prices on the Storm 1,2,3 kit and a 4 and 5 bottle package of Track products -
http://www.bowlingindex.com/polish_cleaners--------------------
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