A friend of mine has the XD40 SC, and I've shot it a number of times. I've only shot it at steel plates (8" or 9" diameter) so I can't tell you what kind of groups I got. I had no trouble hitting them at 10 yards, and I hit most of them at 25 yards, though I had to concentrate a little more than with a longer-barreled gun. But at self-defense distance, it was more than accurate enough.
Personally, I only like shooting it with the extended magazine — I like to have someplace to put my pinky.
"An armed society is a polite society." — Robert A. Heinlein
"After a shooting spree, they always want to take the guns away from the people who didn't do it. I sure as hell wouldn't want to live in a society where the only people allowed guns are the police and the military."
— William S. Burroughs