Haven't been here in a while. This thread did surprise me. Not only am I a retired LEO but also was for many years the chief firearms instructor for the state agency. I'm also a former owner of a Kahr PM9 which I gave a tryout to before deciding on a R9S for myself and got one for my offspring. We both carry them and I put mine on daily and while I have left the property without it, that is very rare.
The 6 rd group I fired out of my son's when first it arrived was published on this forum complete with pics and it surprised even me out of a pistol like an R9S. However the PM9, that I had was another story altogether and would not equal the performance which the R9s's we have are producing. I never carried the PM9 and it now belongs to someone else and they like it just fine. At that time my carry was a Colt Defender .45acp and a SIG 239 .40 and they continued to be until the R9s proved to be as reliable and capable as it did. Since then the R9s has been with me everyday. I trust it completely.
As to pistols that rattle or don't, that really isn't an acceptable standard for a defensive sidearm. I have a small accumulation of WW2 1911A1's that are unmodified in any way and all saw some service after manufacture. Some more than others but all to some degree. Each rattles when shaken and not just a small amount. They, as a breed, are famous for the rattles and reliability. My Colt defender and my SIG 239 both rattle to some degree and I know they both work reliably. The fact the R9s doesn't wasn't even a slight consideration when I bought them. The accuracy and reliability was. I didn't have to do a lot of mental gymnastics to figure out my R9S wasn't designed to be shot a lot at any one outing or that other pistols were better suited for longer range work. The very first time I saw a picture of one I figured that out...and without help too. I think "opinions" are like a well known part of the human anatomy...everyone's got one. That's fine and the only one that matters to me is my own. I think each of us has the right to think what we want and I don't expect anyone to agree with me.
On the other hand I believe through experience, dealing with the public at large, that included more than my share of pin heads, that Ron White is correct when he says that you can fix almost anything but, "You can't fix stupid."