I have two used ones and they are both sub 1/2 MOA. A 25-06 and a 300 RUM. One has a fired cracked bore but still drives tacks. Neither of thes rifles have a thing done to them. Met a guy at the range this morning who has a tack driving 700 RUM Sendero.
I like the older SF's better than the newer SF II's.
What does the fluted barrel give you? Well.... it looks cool and it gives you more stiffness per weight.
They are a factory barrel, and mine (the 300 RUM which only had 20 rounds down the tube when I bought it) is/was a fouler. Been breaking it in and fouling has gone way down.
They dont come with 1/2 MOA guarantees so you are taking a chance, but most shoot very well.
Hope that helps,
-MR