Hmm. P4->P5. It depends... If you want to be able to use P5's other features, such as the Materials room, the Cloth room, the hair room, then certainly go ahead and get P5. P5 supports both the previous P4 renderer and Firefly, you can decide which you want to use for the current scene. If you ONLY want Firefly's rendering capabilities, then I suppose it really only depends on if you want to pay that much for it. Firefly can be superior sometimes; for other scenes the P4 rendere works better. I know that's probably not too much help, but..I hope it helps:-) Cheers, Diolma