I believe, that PanF+ strength's are natural subjects & textures such as soil/dirt/sand, rocks/rocky formations, tree bark, water, and skin/skin tones to name some. Delta 100 covers these elements just fine, just that Pan has that edge I believe in it's grain structure. Delta is good with what's man-made - architecture, day& night, bridges, boats/harbors. Also, Pan is great on a rainy night in the city for those wet reflections off the ground.
Please give feedback on your experiances with these 2 films - agree/disagree is fine.