I've had good luck and bad luck with ER Shaw. The bad luck was a long time ago.
I have Shilen and Douglas barrels also. If I were wanting 1/2 MOA I'd probably go with either and get their "premium". If I were building a hunting rifle I'd probably go with ER Shaw especially with the calibers you're talking about.. The last rifle I built was with ER Shaw - a 375 Whelen AI. I only have Iron sights on it, but it's plenty accurate for what I wanted it for. The bore looks excellent. It doesn't foul with copper or lead.
I use a lot of Shilens and will tell you that it is a waste of money using a select match barrel over the match barrel for a hunting rifle. The only advantage is between your ears.