Looks like I'm still stuck between the J-frame and the PM9.
That's another issue, and a hard call ...
Personally, I went with the J-frame long before the PM9 was even a glimmer on the drawing board, and after shooting a PM9 I'm not even remotely tempted to change my mind.
If I "need" a subcompact 9mm weapon, my CS9 offers me the same DA/SA trigger controllability I've become accustomed to over the years of carrying a full size DA/SA service weapon. While I don't find it a suitable candidate for front pants pocket carry for ME, I've found it slips into jacket & vest pockets as easily as my Ruger SP-101. It's more of a belt weapon for me for most instances, though. The PM9 is smaller and easier to adopt for pocket carry ... but still requires a pocket holster for safety reasons.
The 642 is simply an easier choice for my off-duty concealment needs, when it comes to the ability to carry it in smaller places ... AND yet still retain the ability to control it in the same qualification courses used for our service weapons, which currently includes moving targets and shooting while moving. Training is the key, though, and some folks might find the little semiauto a better tool for their skills and needs.
Also, while I certainly don't intend to step on anyone's toes ... the owner feedback has been mixed on the little Kahr polymer pistol to date ... and the only one I have personal knowledge of belongs to another fellow at our agency. It functioned fine the first time he brought it through our range, brand new and right out of the box ... and then the next time he brought it for qualification he experienced repeated feeding malfunctions, using the same ammunition. This guy isn't an unskilled shotoer, either, being a former SWAT team member and a fellow member (but currently inactive) of our firearms instruction unit. I don't know what this means, if anything ... but I'm very comfortable and confident with the reliability of the J-frame.
One thing that isn't often addressed about primary defensive weapons carried in pockets, and other hard-to-reach places, however ...
And that's the potential for a "less-than-ideal" grip occurring during a stressful draw & presentation. True, this IS a training issue ... but not everyone devotes a sufficient amount of time to this issue, do they? Nor do most public ranges offer the regular patrons the opportunity to engage in concealed draw & presentation practice.
While an improper grip naturally has the potential to create "accuracy problems when it comes to hitting the intended target ... a subcompact semiauto pistol may be a bit more prone to malfunction, due to shooter-induced grip stability conditions, than a small revolver. This doesn't even take into consideration the possibility that the primary defensive off-duty/CCW weapon, or BUG, might have to be used by someone in an awkward, physically compromised or injuried situation.
Risk assessment, and determining which platform YOU can use more effectively, is probably something only you can answer ...
That doesn't mean the rest of us aren't intersted in learning what you decide,and why ... and how satisfied you are with the eventual results.
Stay safe ...