As with all personal choices in handguns intended for defensive use ... it depends on the individual making the informed choice.
Personally? When it comes to subcompact 9mm pistols I prefer my CS9 or G26. When it comes to slightly larger compact 9mm pistols I prefer my 3913 & SW99c ...
Different strokes, and all that.
There are other makes & models, of course.
Of all of the Kahrs that have come through our range, a K40 & MK40 have exhibited functional reliability to the extent that no malfunctions were witnessed over the course of at least more than one shooting session. The MK40 I mentioned exhibited good functioning right from the box, even during the recommended 'break in' period (I witnessed the first 150 rounds fired through it the first day it was fired). A PM40 completed a 36-round COF without any malfunctions. Another PM40 exhibited frequent failures-to-return-to-battery during firing, but it was apparently NIB. Other folks who have brought Kahrs through the range for qualification haven't always been so lucky. One of the other instructors finally had enough of trying to get his PM9 to function and he got rid of it.
I'm sure there are very happy Kahr owners out there. Lots of them seem to post in these forums. I just don't get the chance to actually meet many of them on the range ...
Seems to be an interesting mix of variable experiences and satisfaction with Kahr pistols.
I've never met a displeased G26, CS9, or 3913 owner, though ...
Naturally, you ought to consider test firing as many models as possible through a local range, using quality ammunition ... and perhaps do so on more than one occasion ... so you can be in the position of making the best informed decision possible, after doing enough personal research to satisfy yourself.