My only experience with one is a friend's. He loves it. Hardly a failure to feed/fire/eject according to him, and I know he's put a lot of rounds through it.
He did have to have the plastic mag release replaced because it was being chewed up by the mags and wouldn't keep the mag secure; Kahr put in a new one that has a steel insert molded into it. Also, he had an issue with a sharp/rough edge on the slide shaving plastic off of the grip-frame. He smoothed it out with a stone and says it's okay now.
I've shot it on a few occasions, but just can't warm up to it. Feels great in my hand (when not firing it) but the corn-cob texture on the front/rear grip areas and the light weight of the gun combined with the somewhat hefty recoil of the 40 cal doesn't make me want to put more than one mag per session through it.
It does seem to be surprisingly accurate for such a small gun; good marks for Kahr on that.
I've read good and bad about their plastic-framed guns; some trust their lives to them, others have had reliability problems...