I made the same hard decision today as a matter of fact. I was contemplating against a S&W 642 and a Kahr PM9. Before I narrowed it down, I was also considering polymer framed autoloaders as well but decided against them because of the thickness. And I also was looking at a Kimber Super Carry II because it's slim and I love 1911's but also because of a thumb and grip safety as well as carrying .45's. But ultimately I dropped the idea of a 25oz (empty) gun because at work, I'm constantly moving about and contorting into vehicles and the extra heft is a bit much. Also, I wouldn't wanna stratch that beautiful finish.
Between the 642 and the PM9, I weighed the pros and cons down to:
642
Pros - reliable, no FTF and FTE's, 12lb DAO pull
Cons - recoil, 5rds, I can't reload quickly with a concealable reload strip, .38 special
PM9
Pros - slimmer and smaller print than 642 and quite possibly forgotten about in a pant pocket, 6+1rds, magazine reload is quicker for me and carrying extra mags concealed no problem, 9mm with higher velocity, less recoil than J-frame for possibly better follow up shots
Cons - 6lb DAO trigger pull with no safety, heavy slide recoil spring needs some getting used to.
I chose the PM9. I'm waiting for a holster or two. I still want a 642 as well tho. Maybe later.