I looked at a bunch of the small 9's.
The Kahrs were high on my list, but the PM9 was way too expensive, and the CM9 had the silver finish which I don't like for a pocketable carry gun, and it only came with one magazine. Also they have a recommended break in period, from what I have read.
The S&W Shield was a little too big for pocket carry. Not saying I wouldn't want one anyway at some point, they have had such great reviews.
The Walther PPS wasn't quite as small as I wanted.
The Ruger LC9 was too big for me and too many safeties, loaded chamber indicators, etc., and from what I have read, the trigger is not the best.
I also hear that the PF9 Keltec doesn't have a very good trigger.
So I came to the Beretta Nano. It fits in my pocket, is black, which I like, has a very smooth outline with no obstructions, comes with two mags, and it felt good in my hand. The trigger is like a reasonably light double action revolver, which works good for me., And it was a reasonable price. So I got it. It shoots well for me, and I am very happy with it.