I have used RCBS dies more than any other over the years. I've also used Lyman, Herter's, Redding, Lee and Texan. All worked and if any had some secrete advantage, I failed to recognize it. My favorite dies are Redding, even tho I haven't used a great deal of them. But they are nice looking dies and mine have worked.
Warren Paige wrote in "The Accurate Rifle" that his favorite cleaning solvent was Hoppe #9 because it smelled good; mine to for the same reason. As for Redding dies, they just look good to me and they feel good in my hand's.