I've not had much success developing Delta 100 in Ilfotec DD-X. When scenes are low-contrast or taken on dull days, the tonality is harsh and ugly, and the results are very flat. It is much better only on sunny days with high contrast scenes. I am more accustomed to the rich dark tones of Fuji Acros and Rodinal.
Is there a better developer to use with Delta 100? I have DD-X, Rodinal, Perceptol and HC-110 in my cupboard right now.