I have been using Ilford since 1980 and desire the grain that the 400 can give me. The film is pushable, though with loss of detail, to past 1600 and usable in all environments. My favorite Ilford is no long available in most stores. A contemporary to Kodak Pan X but could be used at 25ASA if you wanted to avoid that grain on a bright sunny day. Versatility could be a byword for Ilford 400.