Skip both and buy a Ruger SR9C!! I love mine! Out of those two I'd take a shield. They are nice guns.
The SR9C is a brick compared to the CM9.
Yeah I'm talking low profile here. I already have a PX4 Storm Compact which is similar in size to the SR9c and if I was going to that size I'd probably just get an m&p9c. I looked at both and they're both nice guns but the Shield seemed a notch above the KAhr.
I put my money where my mouth is and picked up a PM9 this weekend.
It's a runt compared to the M&Pc, SR9C, and Glock 26. Even a J-frame is noticeably larger.
Off the top of my head, the only common guns smaller than the PM9 are the LCP, P32, P3AT, and similar guns.
Remarkably, despite the larger caliber of the PM9, it has less felt recoil compared to the LCP. The LCP is downright brutal to shoot. The PM9 also wears real sights, not nubs like the LCP or J-frame.
The cons to the PM9 are racking it and the trigger. The slide is small so there's not much there to grab, and the recoil spring is stout. If you have hand problems, you may struggle to load a PM9.
The trigger pull is light and smooth but very long. Trigger reset is also very long. It's similar to a DAO revolver in that regard. However, the PM9 trigger pull is much lighter compared to a DAO revolver.
And for those who are curious, the primary differences between the CM9 and PM9 are:
-Barrel. CM9 uses conventional rifling, the PM9 uses polygonal.
-Slide stop. CM9 slide stop is metal injection molded. PM9 is machined.
-Front sight. CM9 front sight is pinned, the PM9 is dovetailed.
-Slide marking. CM9 is engraved, PM9 is roll marked.
-Magazines. CM9 includes 1, PM9 includes 2.