This thread seems to be like a 1970's rerun of what we already know. Rodinal is a fine developer best used on low-speed traditionally formulated films, such as APX-100, FP4+, Plus-X, etc. When used on 400 iso films, it is going to give large grain -- the size depends on the film. HP5+ is at the high end. Tri-X is borderline. Personally, I like the look on APX-100, but would never use it on a 400 iso film. Xtol was formulated specifically to overcome these issues (among others) with higher speed films and if grain is the issue, Xtol is your friend...