I typically stick with factory mags for all of my guns. With that said, I am not thrilled with Kahr mags. The K9 is my favorite pistol, beautiful, well made, accurate, reliable etc... but the mags suck. I don't know why, but the like to spit rounds out if not in a pouch or the gun itself. Put a loaded mag in your pocket, take a walk around the block and you will have a pocket full of 9mm and an empty mag lol.
There is just something weird about the design but I think they have some kind of tweak/fix over on KahrTalk. I will have to look into it one of these days. If I can fix the bulimic mags, and replace the crappy plastic base plates, the gun will be 100% perfect in my view.