Does exactly what it is supposed to... but be super careful and really plan your hole carefully... because if you don't you may undermine the drop out
First--and this is not a flaw with this product--but the two drop outs we repaired using this kit barely had a millimeter of aluminum left all the way around after drilling. So, though we were able to use the provided sleeve and straighten the drop out--and install the derailleur... I have VERY little faith in the longevity of this fix. Because it seems like with very little stress at all, this will (a) bend or (b) crack. So, what's the solution? There's really not one. It's the fault of Trek for making the drop out / hanger integrated to begin with--on a $10,000 bike--from 2006--LONG after the industry standard was replaceable hangers--and for also not making the hanger tab beg enough to allow for drilling in a scenario like this one. What Trek wanted you to do was send the frame back to them and pay a big fat chunk for them to remove the drop out and replace it. Shame on them.
But in terms of how this particular "frame saver" "problem solver" works... I can attest that it DOES work. I've put about 100 miles on the bike (2 hard, fast rides) since the fix and the derailleur is still back there... working. :) For now.