I haven't had issues with anything on the firearm however my understanding is that kel-tec will fix anything that people have reported. I believe there is a kel-tec gun owners forum that lists the various issues by serial number and if you send it back, they'll replace whatever the issue is.
True only if you are the original owner. KelTec changed there policy a few months ago. I've had the P-11 and the PF9 and just couldn't get use to either of them.I would buy another PF9 if the price was right but don't know that I would trust my life to it. For what the guns cost (nowadays) I would look into something more realiable. Best bet is to checkout the KTOC forum for more info.
Kahr vs Keltec isn't a very fair comparison. Kahr is much more $ and quite a bit better in most areas. The Keltec is less $ and functions fine. If the trigger is important to you get the Kahr. Keltec triggers are pretty bad.