I dropped p4 support for p5. Fire fly is a better renderer if it doesn't lock up. The lib support is much better which allows sub directories. My favorite is the material node system. I can add make up, masks, gloves etc to characters all with just using blender nodes instead of special combined textures. For example, if I want bruises I can blend the skin texture with a generic bruise map right on the fly. Same with torn clothes. I can blend the cloth's alpha with a generic torn transmap. Tattoos, masks, makeup etc are real easy to apply and customize. About 1/4 of my textures are now on the fly procedurals instead of bitmap textures. Saves a lot on bitmap space. The material options are 1000% times better than p4's simple 4 materials. Plus you can do true bump, displacement maps and light maps.