Sorry, I don't think ware will be an issue. I might have close to a couple thousand rounds on one sample and it is completely fine with no signs past rub marks which the factory get as well. Also if it ever does ware out just send it back and we will replace it with a new one. I really don't think that will be an issue though. My thought is if someone fire enough rounds on one to ware it out I'd love to see the end result and they deserve a new one!
Yes, Some will do this. The finish blistered slightly on the back in the center of the piston. You will find that it will not spread though. Also the finish is pretty meaningless on the back and really even the front. That is why the factory stopped finishing the factory piston completely on all side and only do the outer diameter in hard chrome. The outer diameter is the important area. If you take a knife and scrap the back (like shaving) as you normally would to clean the fouling from the piston you will see it will not spread past a certain point. Also remember if it ever wares out until a point of failure we will gladley replace it. We aren't going any where!
Here is the thread, that is post #130. Read the whole thread for lots of info on the piston and "diamondized" finish.
In summary: It's a cheap coating for the vodoo magic. All very technical, proprietary, and stuff...
BOTTOM LINE: No one would intentionally make a product that flakes off in your gun. No one.