I had a Ruger PC9 for a time, and it is a nice little rifle. Built like a tank; I wouldn't hesitate to spear somebody with it or smack them with the stock if necessary.
Having said that, I traded it for a Keltec in .40.
The Ruger was TOO heavy, IMO. It also kicked way out of proportion to the round and weight of the weapon. Ruger must have put a 5 lb. bolt in that gun. It left marks on my shoulder after every session.
When I bought it, magazines were expensive and tough to find. Probably not so much the case now...
The Keltec is really a nice little rifle. It folks up in a small package, kicks less than the Ruger even in .40!, and it uses Glock mags which are cheap and plentiful. Not as sturdy as the Ruger, but much lighter and handier.
As somebody else said, the Keltec in 9 can use the big stick Glock mags for excellent capacity, and 9 is the cheapest centerfire ammo going right now.
Andy