Strange that M&P would have finish issues.
It's a stainless slide with a black melonite finish. Should be pretty resistant to tarnishing/rusting. I'd almost wonder if any problems to the finish are because of the user. Time will tell, with mine, though. I just bought it not long ago, and have only a thousand rounds or so with it, so it's not really fleshed out yet. Plus maybe they've improved the finish since these supposed problems existed?
It's a stainless slide with a black melonite finish. Should be pretty resistant to tarnishing/rusting. I'd almost wonder if any problems to the finish are because of the user. Time will tell, with mine, though. I just bought it not long ago, and have only a thousand rounds or so with it, so it's not really fleshed out yet. Plus maybe they've improved the finish since these supposed problems existed?