While I've had my fair share of problems with older S&W revolvers made before the introduction of MIM and CNC production, I've seen an occasional QC issue slip out in a new model revolver.
My M&P 340 had a nicely gouged divot around the yoke screw which had apparently been covered over with a black/purple color of some sort. The first time I cleaned the gun the substance used to color that spot came off and revealed the shiny alloy frame where a bit of metal had been gouged away.
Also, the carry up wasn't quite what I desired on at least one charge hole (although I was told it was actually within spec when I showed it to someone from the company, and it fired and functioned normally) and close inspection of the parts revealed a couple of burred parts, one of which was burring/marking yet another part.
I resolved the carry up and burred parts myself (as an armorer), although I was told the company would gladly do it for me under warranty if I wanted to return it. Once I was done the gun had excellent carry up and has been an outstanding little revolver which has seen a lot of use.
FWIW, since I bought the gun to serve as a "working gun" I expected it to acquire some nicks, marks, dings and whatnot (and it certainly has) ... so I ignored the light gouge around the yoke screw. Obviously, someone else might have felt totally different about this cosmetic issue and might have returned the gun to have the issue resolved in a manner considered acceptable by the company and the owner. I can't presume to speak to that issue for someone else.
As I think I may have mentioned earlier, I've also had my fair share of issues that had to be resolved with a number of new Ruger handguns, including revolvers, too. One Redhawk I own had the cylinder, hammer and trigger replaced when I returned it for a functioning issue.
I just received a fairly new production 442-2 from a fellow who wanted it inspected now that he's fired it for a while. Although I haven't had time to remove the sideplate and look inside, I noticed the carry up was excellent, the trigger recovery was brisk and smooth and the fit/finish of the solid barrel to the frame was as nicely done as someone could desire. So far, it seems as nicely produced, at initial glance and manipulation, as the last 642-1 & 642-2 guns I inspected for a couple of other guys.
Doesn't it just figure my M&P 340 had to be the exception?
I've thought about buying yet another J-frame to add to my collection of them. Maybe another M&P 340, this time the new one made without the ILS (lock), or maybe a M40 or M42. I like J-frames.