Re: Kahr PM9
I've got a P9 which I can comment on. It hides real easy and it's really accurate, with the high end tactical ammo it shoots 2" groups at 25 yards all day long--probably better if someone else was shooting it.
Issues: the magazine on Kahrs is the weak link. For some reason, the geometry of the mag as it goes into the gun causes the rounds to feed up into the chamber at a very steep angle. If you ease the slide forward on a fully loaded mags, a lot of Kahrs won't chamber the round. Course, you're not supposed to do that anyway, with any auto. At full speed it feeds great.
And for some reason, the rounds seem to come out of the magazine when you keep a spare mag in your pocket. This sounds kind of retarded, but it's true. Also the Kahrs eat recoil springs super quick. Also, Kahr used to say you can't run gold dots in them, but that's all I use and they run fine.
Anyway--with my 7 round mags and every type of ammo, my p9 has gone bang every time except with Wolf ammo it started getting light primer hits after 500-800 rounds. I figured out the firing pin channel was dirty, cleaned it and the light primer hit problem went away. Now going on about 2000 rounds into it, very hideable. It seems to hate the factory 8 round mags, though, no matter what ammo I use.
Long winded way of saying they're great, but a bit more finicky than some other guns. Not 1911 finicky, not to say you can't get them to run 100% all day, but require more upkeep than glock sig etc. You gotta keep them clean, detail strip every 750 rounds or so, and replace springs every 1000 rounds, max. Hope that helps.