Here is one comparison I made, both processed in Rodinal 1+50. CHS II rated at 100 and FP4 rated at 125. There are some odd marks in the sky on the Adox, upper right side - no idea what these are, more likely to be my fault than some film problem. I've downsized this jpeg so it fits on the screen - the original scans are much bigger so I can look in detail at the dark and light areas and there is not much difference between the two films. A few months ago I was comparing FP4 to Foma 200 and the differences were significant, with Ilford being superior.