Been spending some time on King Arthur's website
First off, I was always a "flour is flour" kind of person until recently when I started diving more into the science of bread. Even after that, I was always a AP flour is AP flour kind of person. I've been using King Arthur recently, and I have to say, I'm a believer. The flour just seems better to me. Products turn out better, and I don't think it's just my mental effect.