Go with the Kahr, PM9, it's superior to the other guns mentioned, having had most If not all of them, they each have their own special annoyances. the Shield was not that small or light, and mine in 40 dropped mags, the LC9 had the most wobble in a trigger I ever saw, I even called Ruger on it and they explained that the gun had problems seizing under rapid fire so they left the gap there on purpose, "even with the RTK "Galloway trigger" it became unreliable due to the flimsy trigger spring, the Rami, "I never owned" but had a lot of unhappy owners complaining of ftf's and that was enough for me. The Bursa is way too big and not enough street time, the Beretta is a nice gun the PX4, but again way to big and heavy. I like the Nano, but some say it also has feeding problems. The Glock 26 is the perfect gun if your criteria is something that works every time you require it to.But the PF9 is the perfect size and comes in loaded with 6 +1 at 20 ozs.The rest are all heavier except the Ruger. "Nothing fancy", calls the PF9 the perfect concealed carry gun in 9mm, and carries one himself, I mentioned this someplace else only because anyone who has tried every gun out there and can carry any of them, has chosen this one.
The lc9 does function fine if you don't mind the trigger, I still would like to try the Nano, the Shield is ok in 9mm from everything I read, the 40 is the problem, although it is still larger than the lc9 in the pocket. I can't find anything wrong with the Kahr, and my first one "when they came out 18 or so yrs. ago, was a bomb", I think it was a MK or P9, It fired one round at a time. But the new one works great, I have fired everything I had in the drawer through it and it hasn't hiccupped. I ran 5 mags used and new, and no problems, It does bite a bit, but they all do depending on your grip and tolerance. If you want the smallest most reliable 9 I have seen it's the Kahr, I only carry that or the glock 26. I would try the XDS in 9mm as I carry it's 45 caliber cousin also. For the weight difference you may as well carry the 45 as there is none. The good thing with the Xds is you can throw a light on it and use the extended mag, and you have a full sized gun if you need it.
Everyone is different and some like a gun that an other doesn't care for. I always like to see for myself, but most times I am disappointed in what the actual gun is like compared to the hype. Let's face it, if it works for you then it's terrific. I just want to make sure when that day comes around again, I have the best chance of it going bang every time I pull the trigger. Many have disappointed me on that front. Glock always delivered for me, and the xd series also. Kahr is a pleasant surprise so far, had mine apart today and it is well made, the outside is not impressive, but they make it right where it counts.