I've got one with the stanard rear sight setup (not the ghost ring). I love it, and it's my go-to gun for home defense. It shoots 9mm (including +P) rounds like a 22LR. And those 9mm rounds are very lethal from that longer barrel.
I have the original magazine in a box collecting dust. I keep it loaded with an 18 rounder, and also have a super long 30 rounder ready as well.
I used to have a Marlin carbine and feel this Ruger is the best thing going in a carbine. It's amazing how easy it is to hit with this, vice staying competent with a handgun. I can put 10 rounds downrange into a 3 inch group at 10 yards in about a second or so without really trying. Of course this is under a no-pressue situations. I've yet to point the gun in anger.
B. Noz.