I am currenly using 3 Pac-Nor barrels, all 26" long. One in .25-06 AI with 5-groove rifling and 1 in 10" twist; one in .260 with polygonal rifling and another in .260 with 3-groove rifling. Both 6.5 mm barrals have 1 in 8" twist.
All barrels produce excellent precision with well-tuned loads. The polygon barrel, which is on my Tikka 595 hunting rifle, performs better with loads approaching maximum pressures and delivers higher muzzle velocity than the 3-grooved barrel, which is on my Hunter Class silhouette rifle. The polygon barrel also retains a lot more copper fouling and takes longer to clean.
I've found Chris Dichter to be very attentive and easy to discuss things with. His prices are fair, his barrels are good and he delivers on promised dates.
I also use Shillen and Douglas barrels, and have used Schneider barrels as well. Nothing wrong with them, but I prefer Pac-Nor.