Many good comments already. I'd add, if you have experience shooting revolvers double action, the PF-9 and P-11 are similar in length and weight of pull (with the PF-9 a bit lighter, while the P-11 has true DA, double-strike capability) to a revolver. This long, revolver-like trigger pull allows them (and P-32 and P3AT, also) to be safely carried with the K-T belt clip, that mounts along right side of frame (sorry, lefties). This gives an exceptionally thin, unobtrusive, and comfortable concealed carry. The only uncomfortable aspect to any of them in this style carry, is the leading picatinny prong on the PF-9.
It "kinda digs" into the belly
I carried a P3AT for a few years with the belt clip, then found a PF-9 for a song, in a pawnshop. Shortly thereafter, came across a P-11 in another pawnshop for too little to pass up, and switched to wearing it. If I had stuck with the PF-9, I'd have taken a dremel sanding drum to the pic rail--it would be a quick & easy job, and K-T sells the FRP grip frames for cheap, if something went terribly wrong.
QC/Customer Service: QC seems to have been somewhat spotty, at least in the past. The PF-9 had odd production defects in bore, and K-T replaced it for me. I emailed them, snail mailed the barrel in, and they sent a new one. Had a trigger axis break, same deal: mailed it off, they sent a new one. No charge for either part. I give only positive regards, for their customer service.