I currently own a XD subcompact 9mm and its a little bulky and heavy for EDC I do like the 13+1 capacity at only 6.25 inches long and 4.75 tall its 26oz empty. its around 35oz loaded.
I am looking into the Glock 27 so I can pratice with 9mm if i get the conversion kit. The glock is identical in length but a little shorter in height at 4.17. That is going to be my biggest factor in concealing. I am a tall and slim build and dont wear oversized clothes. The glock isnt much thinner than the XD SC but a half inch shorter in grip length and also lower bore axis so should be less recoil but less rounds but weighs less. Widht is 1.18 27oz loaded and 9+1 rounds
Second option is a Kahr pm9 I read mixed reviews on this gun but more recent reviews are better than old ones. gun seems amazing for concealing 5.3 length height 4.0" and weight only 14 ounces right at 20 ounces loaded 6+1 I dont care for but its the price I pay for small gun to conceal 100% of the time. The width is only .90 inches. To have the 40 caliber I would lose a round and go to 5+1 which I dont like that idea.
Its either carry the current XD SC 9mm 13+1 heavy and bulky-dress around it and get a good holster.
Glock 27- Weighs less, not sure on thickness compared to the XD, less rounds 9+1, shorter grip.
Kahr pm 9- smallest gun, light, thin, only 6+1 for capacity.
Other options-Please post
Whatever gun I go with I plan to carry a spare magazine or two if I am going far out of town late at night or a unsafe area. 1 spare mag on me and 1 in the vehicle unless I feel its a good idea to carry both extra mags on me. Also I plan on carrying a BUG small 380 acp prob either a kel-tec or a ruger lcp back pocket more than likely. With time I want to invest in a subnose hammerless 357/38spl S&W j frame and ankle carry only when I am going out of town and feel the need for an extra gun with 5 powerful 357 rounds.