I also have a CM40. It is everything you would expect from a Kahr (nice fit and finish, good trigger, accurate, and reliable) and from a .40 S&W in a tiny gun (recoil, recoil, and a bit more recoil). I find it perfectly manageable for a defensive gun. Not a ton of fun after a bunch of rounds. It should conceal really well.
I still need to pick up a pocket holster for mine, so haven't really carried it yet. I have put several rounds of white-box FMJ and a couple-dozen JHP defensive rounds through it with not a single issue. The slide (thanks to a super heavy spring) is still exceptionally stiff.
The CM40 is my daily pocket carry. I expected a lot more recoil with the info on the web. Recoil isn't bad and the accuracy is very good. It feeds JHP's great. Overall I'm very pleased with the performance.
I have owned one for about 6-8 years. Shot 300/400 rounds thru it. A very reliable gun that I feel is about perfect for concealed carry.