I read a piece many years ago by John Sexton on TMAX films, and he said something to the effect of "after using TMAX films for two years now, I am beginning to get intimately aware" of the emulsion. It's so true. We think we can do a roll here and a roll there and get some consistency in our work. Great artists know their materials, their strengths and limitations, and they max them out.
That being said, I periodically switch from TMAX to HP5, but still use Diafine. No one can tell the difference. I can't even tell the difference. So I think the endless obsession with film and developers is a bit overdone. Ansel used TriX. Avedon used TriX. Callahan used TriX. Salgado used TriX. etc. Does their work look at all alike?