I haven't tried one of their AR products, but my Lilja barreled bolt guns are the most accurate thing I have ever touched. I don't pretend to be the greatest shooter on the planet, but switching to the Lilja barrels cut my groups down significantly.
Since you say it's for varmint purposes, I also have a Shilen AR barrel in .204 that drills every little critter a can put crosshairs on.
My "budget" AR barrels are Black Hole Weaponry products (I guess they call themselves Columbia River Arms, now?), which are still more accurate than most in their price range, and good enough to have won some local competitions (although not in my hands).
Lastly, the only factory AR barrel I haven't felt the need to replace is my Rock River. I heard a rumor somewhere that they outsource their barrels from Wilson.