I use both films quite frequently. PanF in both MF and 35mm, FP4 in MF only. Both films are superb in their rendition of tone and contrast. I like FP4 pushed to ISO 200 to give me more shutter speed options with little or no perceptible difference in grain size. It can be very contrasty, so use filters sparingly. PanF is has just gorgeous characteristics in tone and acuity. Even at 35mm the film puts out relatively grainless negatives with such warm velvety texture in some instances and cut-your-eyeballs-out sharpness in others. It remains as my second overall film to Efke R25.