Vaquero is correct: there is a history of some issues from time to time with some guns. But there is also a history of incredible customer service.
I've been one of the lucky ones: my PM9 has never one time failed in any way shape or form, and I didn't even learn of the suggested break-in until after I'd fired about 150 rounds -- I just took mine out of the box, cleaned it up and lubed it a little bit, and sent three 50 round boxes into the side of the berm behind the target without failure. But that doesn't always happen, and I think Kahr understands that.
I honestly swear by my PM9. That's why it's on me 90% of the time.