They're supposed to be pretty good. But some people will tell you that Armalite's are better. Hooper on snipershide has been doing group buys and everyone seems happy.
Keep in mind that a semi-auto is likely to not be as accurate as a bolt gun. Primarily because you load to mag length as opposed to fitting the chamber/throat that most bolt shooters do (even though they also have a mag the tolerances aren't the same). Also, semis generally have looser tolerances so things work.
That doesn't mean that one of the semis won't be all the gun you can handle anyway. I do feel like my 18" SPR AR is easier to shoot smaller groups than my .308 bolt. It's probably just my skill level showing through.