I carried concealed a Walther PPK in .380 ACP for over 12 years. I shot it often and I shot it well (at the range and at pistol courses). Thing is though, I have big hands and I was getting "bitten" on the webbing of my hand when the slide came back during firing. I simply dealt with it because I really liked the PPK. In 2002 I fired a Sig 232 in .380 ACP and instantly fell in love with the pistol. It ultimately is not any bigger than the PPK, the grip has a slight palm swell and it also has a slight "beaver tail" on the top of the back strap of the grip preventing me from getting bit by the slide when fired. I traded in my PPK in 2002 and since then I've been carrying concealed the Sig 232 in a Galco open top holster as often as I can.
Thankfully, I've not ever had to use it.

Remember, some guys will give all kinds of advice based on an opinion without any substance behind it. I approach the debate of gun, caliber, and role from a very open minded position. I've been reloading and shooting for over 20 years now and I've been in law enforcement for 11. I've been to multiple shooting clinics including Thunder Ranch and multiple LEO courses. Am I an expert? No, but who is and by what standard? Here is my take on CCW handguns: As for the gun, for CCW purposes it needs to be small. A full size Beretta 92, 1911, S&W 686, or other such full size handgun defeats the purpose in most cases. They are simply too large and heavy to keep concealed by typical means. In terms of caliber, remember that the shooter *needs* to practice with the gun and if it is not fun to shoot or able to be shot in a comfortable manner to gain good and consistent accuracy then what is the point? IMO, it is real simple. The smaller the gun and the larger or higher pressure the caliber the less likely a person is apt to practice with it thanks to a healthy recoil and muzzle jump. Sure, some shooters can shoot anything at anytime and do well, I'd like to think I am one of those people. But to the bulk of the shooters I highly suggest that the smaller the gun the smaller the caliber. With that in mind, I think the .22LR and .25 ACP are too small to be of much use in defense especially if the target is wearing a winter coat or even a heavy sweatshirt. On the other hand, the .45 ACP, .357 Mag, and even the .40 S&W are too big because of the reasons mentioned earlier (small gun and big caliber = hefty recoil, muzzle jump, noise, and a tendency to be less accurate). The .380 ACP, 9mm Luger, and .38 Special are about perfect when considering the size of gun that has been suggested, the role in which the gun will be used, and the ease in which the user can practice and learn the gun for CCW purposes. Last note: in regards to what brand all I can say is this: avoid the cheap POS's as much as possible. The Lorcins, Phoenix Arms, etc. They are truly junk. Otherwise you cant really go wrong.
This is all my opinion, but after shooting the dozens and dozens of firearms and calibers, in a multitude of different roles, I feel I can offer a new guy and maybe even an "old dog" a few insights as to what to look for in a CCW handgun.