I have had both T/C Factory Barrels and Barrels from some of the Custom Makers (Bullberry, Virgin Valley Custom Guns, SSK Industries and On Target Technology). I guess it all depends on what you require from the individual barrel.
To me if this barrel is to be chambered for a Deer Hunting Cartridge / Caliber i have found that the T/C Factory Barrels provide what I require of them. Now this is not to say a Barrel from one of the Custom Makers will or will not be more accurate.
On the other hand if the Barrel is to be used for Varmint Hunting or Target Competition then it becomes a little different. The accuracy requirements I place on a particular cartridge / barrel / gun to be used for Varmints is more stringient than one to be used on Whitetail Deer. While I have had T/C Factory Barrels that fullfilled my requirements, I also had to do considerable load testing / developement in some of those barrels to get the accuracy required. The Barrels I have had from some of the Custom Barrel Makers seemed to be much easier to find that just right load for and or shot more loads equally well than T/C Factory Barrels in my experience.
The bottom line is it all depends on what you require from your Barrel. If this is to be a Deer Hunting Barrel and your requirement is for 1" 5 shot groups at 100 yards from the bench, then I am sure yuo'll be able to achieve your goals with a T/C Factory Barrel. On the other hand if your requirement is 1/2" 5 shot groups at 100 yards from the Bench I think you'd have a better chance of reaching your goals with a Custom Job.
Larry