The only weakness of the Poly finish is that it is fundamentally a plastic, and things like ACETONE will eat it up. Avoid acetone and any cleaner that has a plastic solvent, and its almost indestructible.
(I've had it on two different CZs -- a 75B and 40B -- and I disliked it at first, but have come to appreciate just how durable and wear resistant it is. Several shooters on the CZ forum have had problems with flaking, however, and that sounds like a case of poor preparation prior to the coating being applied. I also have a CZ-85 Combat in satin nickel, and it seems just as impervious, and is downright gorgeous."