Most folks are not really good enough shooters to be able to tell the difference between factory and custom. I've owned quite a few factory barrels and have only had a few with difficulties. The 223 Contender barrels have given some folks problems. I had one that was terrible, but had it rechambered to something slightly longer. Now it's incredibly accurate. There's been some negatives shared about the 25-06 Encore barrels. I had one that wouldn't shoot the heavier stuff, but wasn't bad on the lighter bullets. Unless you really want something exotic, you can probably get what you want used from either the classifieds here or from Ed Kirkpatrick. If you're willing to pay for something more interesting I wouldn't hesitate to recommend Virgin Valley or Dave Van Horn. I have bought two new barrels from VVCG and had two rechambered by DVH. All were excellent. Bullberry seems to do good work, but the wait is significant. MBMCO has a growing positive reputation.
Rick