I think there are many that make great barrel-blanks, and I don't think there's a single barrel maker out there that consistently makes poor blanks.
I have found that Shilen makes very consistently good blanks, and they are great to work with. I'm sure Krieger makes a fantastic blank, but for me, Shilen was just much easier to deal with, and gave me great service and pricing.
The AR is not the perfect platform to assess the true finite accuracy of a barrel blank. I think most of the top named barrels will shoot better than the AR platform is capable of.
I will say this though: I have tried other barrel makers, and some were hit and miss as far as fine accuracy. With the Shilen barrels I have used, if I do my part, it will be a very accurate AR barrel. They are VERY consistent, barrel to barrel.