I have no real knowledge of the Kel Tec, but the Ruger is a very sturdy gun, and not prone to fouling and hang ups. It also is not all that accurate. The new ones should group 2-3 inches, the old ones more like 4 or 5. But it will spit out ammo reliably.
I sold mine years ago, when I discovered my SKS was actually more accurate.
Ben