I'm not worried about it in my firearms, because as mentioned, I clean after every trip to the range anyway, so even if it's cheap, dirty powder or the casing leaves metal in the moving parts, it all gets washed away anyway before it can do any real harm. I've shot just about every different kind of ammo available through my 92FS, and I do not see any abnormal wear on it anywhere. ...and it was a police issue weapon before I bought it, so it was used hard before I got it as well.
But what worries me is long term storage of the ammo. I like to keep a healthy amount of ammo around so I'm not "hand to mouth" on ammo. If I want to go to the range, I'll buy a few hundred rounds, put it away, and shoot some of the oldest ammo I have.
however, to save some money, I have bought the cheaper russian made ammo, but because of that, I've stopped my First in, first out of my ammo inventory, and will use up the steel stuff first.