I've been carrying an electroless nickel (factory finish) K9 since around '96 and love the damn thing! Its compactness and substantial ordnance steel construction is what drew me to the Kahr, but after several thousand rounds of various FMJs, JHPs, JSPs and handloads of just about every powerlevel, the 100% reliability has absolutely won me over.
True enough, in the beginning I had to send my K9 back to Kahr for "repairs" as I had the K9 fail to return to battery due to some American Ammunition FMJs failing to fully seat and I mistakenly attributed that to an over-tight/out-of-spec chamber. In my defense, this was back in the mid to late 90's and well before the non-resized crap quality of American Ammo became common knowledge. Kahr went over the K9, polished up the interior and simply included a note with the K9 asking me not to fire garbage through their product. Touché Kahr, touché.
I only replaced the recoil spring with a new one (Wolff) after the 3,000 round mark a few years back as a precaution... I suspect it likely would still be working just as well today if still on it's original spring.
This K9 is absolutely controllable even with Winchester's stout 127gr +P+ Rangers, though this didn't come as a surprise as I had already knew the K9 was orginally built around Cor-bon's hot 115gr +P JHP.
What did come as a surprise was the seemingly match grade accuracy. I can print tighter groups with this pistol than with my G19, despite the 1/2" barrel difference and shorter site radius.
Though heavy for its size, the K9 is built exceedingly well. I can't say as much for Kahr's Polymer series handguns as I've never dealt with one. However, I simply cannot say enough to exalt the K9!
Hell, the electroless nickel finish still doesn't show any significant wear from the hundreds of draws from the nylon DeSantis promotional belt holster my K9 came with (which I still find an ideal mate to this pistol for daily carry). My only issue is that my wife has essentially adopted the K9, leaving me to carry the much larger Kimber classic custom 1911 (the only other pistol I'm equally proficient with). But hey, that's ok... I'm a 1911 guy anyway.