P4 stuff works in P5. P5 stuff doesn't work in P4. I can see asking for P5 specific MAT files be included in packages, but asking for P5-only stuff means cutting off at least half the potential market. The hair room is still buggy for me. Yes, I have the latest patch. I've also seen very few decent P5 hair models. Dynamic cloth - I can't figure that room out even with tutorials so why buy dynamic cloth? I'd rather take 5 minutes and post work any poke-through with a regular, conforming cloth. Firefly is freaking slow on my machine and in many cases looks a lot worse than the P4 rendering engine. Shadows are more-or-less wysiwyg with the P4 engine. Firefly's shadows seem to be random. (And the latest patch screwed up one type of shadow anyway - I can't remember which one.) The way I see it, about half the users may have P5 by now, but once you look at how many of them are successfully using the advanced features, that potential market for P5 only stuff is far lower. P5 functionality as well as P4/PP is fine, but most merchants can't afford to support P5 only. Cheers!