Proof is in the pudding. Don, among others, has helped me very much with my film processing, getting it under control by re-learning basics and eliminating fancy work. By learning how to adjust agitation to exposure and lighting conditions, I have effectively opened up a whole new spectrum of possibility, and the cool part is - it's with the same materials every time!
I have used Kodak TMY-2 for a good while now, and while cost has forced me to use some cheapo Arista film now and then, the TMY-2 is my mainstay. Replenished Xtol is my developer of choice, and by exposing the film from EI 200 to 800, and subsequently altering development time and agitation intervals from 1m all the way to 5m I have learned how to control what my prints are going to look like.
This works, ladies and gentlemen, and I proved it to myself by doing it; with great guidance.