I've had a PM9 Covert (short frame, standard length slide/barrel) for not quite a year.
I like it enough to carry it daily as my second gun. It usually surprises how easy it is to shoot for a small gun.
Mine had a few stutters early on with the Cor-Bon 115 +P JHP that I usually carry in 9mms. The Sierra bullet it uses isn't the easiest feeding bullet, so it wasn't a huge surprise. I used either Federal 9BPLE 115 +P+ or some Federal 124 Expanding FMJ that I had around until I got some Winchester Ranger 127 +P+ to try. That has worked fine.
All ammo tried has shot OK accuracy-wise.
For accuracy tests, I always shoot carry guns with a magazine-full, at 15 yards, handheld like I would "for real". I shoot as quick as I get a decent sight picture. Just trying to make it clear that the gun is probably capable of better than the following.
Cor-Bon 115 put 7 rds in just over 3", and hit 1" low.
Fed 124 EFMJ: 4" (all but 1 in 2.5"), and on the point of aim.
Winchester 127 +P+ Ranger: 2-3/8", and 3/4" high.
Regarding Kahrs in general-
I would avoid the mini Kahrs like the MK9 and MK40.
I had an MK9 (steel frame, compact) for a while a couple of years prior. That didn't work out so well. I often had incidents of the slide failing to completely return to battery. A nudge on the back of the slide would fix it, but it didn't make it OK.
It seemed to me, that when working the slide by hand, there was very little spring pressure forcing the slide closed at the last bit of it's travel. Others I hand cycled were the same.
The MKs use a telescoping, dual recoil spring system, and that last little bit appears to be pushed along by only one of the springs. The "bigger" Kahrs use more conventional spring system, and all of those I've handled felt like they had enough spring pressure.
A small gun that tends to be carried where it collects lint and crud to impede cycling doesn't need to start with a weak recoil spring setup.
But that's just my opinion.