I looked at the Ruger PC-9, and I liked it, but I liked the Kel-Tec Sub 9 even more. The Sub 9 is more expensive and I haven't seen very many, but it is one cool rifle that can be folded in half. It shoots well too. Unfortunately, cleaning it has become a gigantic task which has already eaten its share of my flesh and patience. The instruction booklet says stuff like, "don't pull the pin all the way out" (which is very easy to do) then "PING" you've just shot a microscopic part of the gun across the room. It also says, if you release the hammer when the gun is disassembled the gun will become inoperable. Ok, by accident I did this too. I fixed it, but now I know every hidden spot on the gun better than on my wife!
Ok, 'nuff said. I like it. Pistol cartridges are cheap, don't recoil much and with the Sub 9, offer a lot of mid-range accurate firepower in a very small package.