CM9 for me.
I picked up a new CM9 on sale for $329 out-the-door back in February (new store opening sale for Palmetto State Armory). That's literally half the price of a new PM9.
Why not throw the MK9 into the mix.
The mk9 is not that far ahead in price with the pm9, yet the weight help firing control for some while others focus on remembrance.
I've shot the CM9 back-to-back with my father's MK9 (basically the same pistol as a PM9, but with a steel frame) on numerous occasions, and, suprising as it may sound, there is no discernable difference the way they handle or shoot, despite the weight difference with the MK9. Felt recoil is about the same; they are both surprisingly soft shooters for such small 9mm pistols.
Yes, the PM9/MK9 has a nicer looking slide, but let's face it - these are conceal carry guns that no one is supposed to see anyway. Night sights are readily available for the CM9, and the lack of a second magazine in the box is easily remedied.
The only real functional difference between the CM9 and PM9 is the traditional versus polygonal rifling. That said, the short traditional-rifled barrel of the CM9 is still easy to clean, and the miniscule amount of muzzle velocity that the CM9 gives up is not worth the price premium of the PM9 to me.