Both weapons seem rather well made, based upon handling and examining them ... My personal experience with the Kahrs is rather limited. Only a couple of our folks have bought them for off duty weapons, and we seldom see them as weapons of choice for CCW folks in our county ...
One of the ones used for off duty was an early blued 9mm, and it just wouldn't reliably return to battery ... as often as once every couple of magazines when I watched the shooter. The recoil spring was certainly strong enough. As a matter of fact, it was so strong the "smaller statured" shooter experienced problems retracting the slide to load it. The shooter's grip strength might've contributed to the observed problems, as well. Some minor work by one of the other armorers, and ordering a slightly lighter recoil spring, appeared to resolve the problem. The other shooter has a .40, and he required a heavier recoil spring before he was satisfied enough to carry it ...
Regarding the top rounds "popping out" ... This isn't restricted to any particular make or model of pistol, if it's the result of either improperly performed "press checking", or very slowly manipulating the slide to strip the first round from a magazine, and "easing" the slide forward.
I've watched it occur repeatedly with folks in both instances. Performing a "press check" with a very slow and extended slide manipulation can easily displace the top round forward as the slide is returning to battery, as the coefficient of friction (between slide stipper rail & top round) is increased during the slower forward movement. This generally doesn't occur during shooting, as the slide velocity "lessens", or overcomes the friction between these surfaces (unless there are problems with the magazine lips and magazine spring strength, of course). When shooting the pistol, recoil generally returns the round to the rear sufficiently to strip, feed and chamber it during shooting, although it might simply fall out if the magazine is first removed to top off ...
I warned one shooter against performing his version of a press check once, as he was retracting the slide almost an inch to the rear, and very slowly and gingerly pushing it forward to return it to battery. It immediately malfunctioned while feeding the second round during fire both times he did so ... He couldn't understand why it occurred, and couldn't believe I'd warned him beforehand it was likely about to occur, each time ... Oh well ...
It doesn't have to be done by retracting the slide very far, and there's nothing that says you can't remove the magazine and tap the top round firmly to the rear after doing a press check ...
Chambering the first round by "helping ease" the slide forward while stripping the top round, feeding and chambering it can accomplish the same displacement of the "next" top round in the magazine, as well ... and I've had some extra power magazine springs increase the "upward pressure" enough to increase the "friction", as it were, of the top round against the slide's stripper rail ... and cause the same effect. Once the springs "broke in" this tendency disappeared.
I've watched a LOT of rounds fired through both 3913's & CS9's. I own both. I'm very satisfied with the CS9. It "feels" less comfortable in my hand, but I can easily equal, and often exceed, how accurately I can shoot it compared to my 3913. Ugly little pistol ... but VERY reliable and accurate. The shooter must adapt to the heavier DA trigger stroke, though, which is the result of the shortest hammer spring used in the S&W pistol line up, necessitated by the short grip height.
I'd think the personal choice between DAO and DA/SA would have a lot to do with whichever design is selected ...