+1 .. can't get any simpler than this. if your CCW is hard to carry/uncomfortable/etc. human nature says one is less likely to carry. my test ... is your weapon comfortable to the point of almost forgetting it's there?
for me it's S&W 340PD with full house .357 ... what ever (if any) limitations of your choice needs to be addressed. for a 340PD it's extremely difficult to shoot accurately with a DA snub-nose 11oz revolver. for me this meant extensive gunsmith time on trigger combined with many hours of trigger time with a double action revolver and cutting back on shooting semi-auto pistols. your mileage may veri..
if you cannot place all five round inside a pie plate at 10yd ... then you are CCW the wrong pistol and/or not getting enough trigger time.
When I don't have to tuck in my shirt, I carry a Glock 22C in a Milt Sparks VMII. If I do have to tuck in my shirt, then it's a Kahr P9 in a Crossbreed Supertuck. I carry a spare magazine with either. No comfort or concealment issues at all.
The hardest would be a Beretta 92. It's heavy, bulky, and has a hammer. HK USP's and USP compacts can be a real chore to conceal, as well.
Glocks of any size can be concealed on me easily. Especially in a Crossbreek Supertuck. To the dismay of some of my friends, I remembered carrying a Glock 24L in my crossbreed, ROFL. The look on their faces when I drew it out of the holster was priceless. I carry right at the 2:30/3:00 position, so barrel length is of no issue for me. It's usually more about the shape of the grip and the slide for me.