Next best thing to a Walther PPK. But for a lot less money. In my tests the makarov round is just a wee bit weaker than a 9mm Luger but way better than a 380.
I've chronographed 'em. I'll take a 115 grain XTP JHP at 1263 fps vs a 94 grain JHP (silver bear, probably won't expand from what I hear) at something shy of 1100 fps any day and twice on Sunday. That, and 11 rounds of firepower, and near equal accuracy and 14 unloaded ounces in my pocket, is why I prefer My Kel Tec for carry. Don't mean I don't like the little P64, just believe 9x19 is far superior in power and the gun I have is lighter and carries near twice the firepower. I've been toting that Kel Tec for 16 years and haven't found anything that I prefer to it. It's got a 5 figure round count and is as reliable as the little P64, meaning I've not had a jam with either when feeding preferred ammo. The KT has a dislike for 147 grains, but eats 116ers like candy.
Yeah, the 9x18 is superior to the .380, but there ARE some .380s that can keep up with it sold by Buffalo Bore. However, I wouldn't feed that stuff in an LCP type gun, myself, might be a little rough on it. There is no +P SAAMI rating for .380 and these rounds just HAVE to exceed SAAMI pressures to get what BB advertizes for 'em.
I compare 9x18 to .38 special in a snubby, but I shoot a 158 grain HP in my snubby, so again, advantage snubby.
Regardless, I think the 9x18 is fully capable as a self defense round, but I don't get carried away about its supposed superior power to the .380, not THAT much difference.
One thing about the P64, too, I hope it never breaks 'cause I don't like my odds at finding parts for it. Seems very well made, though. It's a neat little pistol and I love shooting the thing with cheap Monarch FMJ ammo 9.95 a box from Academy.