I have a pm9 and love it, but it wouldn't be my choice for a new gun. But if you happen to find a good deal on one used, snap it up!

If you want an inexpensive, lightweight workhorse that you don't mind getting scratched/banged up, get a cm9 (unless you like changing sights). And if you want a lifetime gun that you'll baby and maybe pass down to your kids/grandkids, get the mk9.

If you're in the market at the PM9 pricepoint, do check out the sig p365. Just a smidge wider/heavier than the pm9, but with more capacity and faster follow-up shots. If you go that route, try to get one made in June or July to avoid some of the issues on early production units.