I have only fired the Kahr on a very limited basis, but found the recoil of the K40 to be snappy. I also thought the gun felt top heavy, but others disagree with me on that point.
I have owned a G23 since they first came out in 1990. I bought it at the time because I thought that it was the best compromise between size and power available, and it holds a goodly amount of ammo.
I still carry this gun. In comparison to the Kahr, I find the Glock easier to shoot. The G23 is snappy, as others have pointed out, but I think a tad less than a Kahr. If you have a tendancy to limp-wrist, you will have problems with this pistol. If your technique is good, you will get good results.
I do not intend to sell mine. Ever.