I have only processed a few sheets so far but it seems to take longer to develop when using semi-stand techniques diluted than does FP4. My Normal for FP4 ranges 23-26mins but P400 needed closer to 30minutes at my dilution of 3:2:500. I find I have grown accustomed to shooting FP4 @100 . Not sure I need higher speed film for the landscape work I do. It seems to put the exposure time right in the middle of my weak spots on my shutters. Example 1/30th on my shutters can be anywhere from 1/10 to 1/50 so I have to use f-stop adjustments or add ND filters if I want to create blurred water.