Well, I have Hornady, RCBS, and Lee dies in my reloading room. I don't have hundreds, but I do have more than one set if dies. The only difference I have found has been price or availability. Most of them are Lee since I can't tell the difference in a loaded round, why pay more?
That being said, One set of Hornady Custom Dies in .303 Epps, because no one else wanted to match the price. 7.62x39mm in Hornady, Lee, and RCBS because I got each of them when I HAD to have them. RCBS and Lee for.223, .30-06, 8x57mm. All the rest are Lee. I have a Rockchucker press, Lyman and Pacific powder measures, RCBS Rangemaster 750 digital scale, Lyman 550 scale, challenger press, turret press, classic cast press, and a classic cast turret press. I have Lee case trimmers and a hornady case trimmer. RCBS, Lyman, and Lee shellholders. Lee, RCBS, and Lyman case prep tools. My loading blocks are homemade, my trickler is homemade, my universal decapping press is an arbor press from Princess Auto that I modified.
For me...it is all about price and the end result. No one can convince me that Hornady or RCBS equipment at twice the price will make any better hunting and plinking rounds than Lee. That being said, I threw away the Lee powder measure and the scale since they DIDN'T do the job I needed them to do and went back to those that did, in those instances, I NOTICED a difference and used the better stuff (used product in both cases).
Edit: Only trouble I have ever had with customer service was with Redding when I was starting out and using borrowed dies. Broke a decamping pin, phoned for a replacement, cost me $4 plus shipping, IIRC. NO FREE, NO QUESTIONS ASKED WARRANTY. I have since had the greatest of service from both Lee and RCBS.